This chapter describes features of IRIX that are useful to the System Administrator. Administrators coming to a UNIX-based system from other environments will find this chapter valuable in reducing the amount of time necessary to perform some tasks. Others may find hints and features that they did not previously know.
The following features are provided as part of the IRIX command shells.
There are shortcuts available to you when you wish to define large numbers of files or directories in your commands. These shortcuts are known as “regular expressions.” Regular expressions are made up of a combination of alpha-numeric characters and a series of punctuation characters that have special meaning to the IRIX shells. These punctuation characters are called metacharacters when they are used for their special meanings with shell commands.
These shortcuts are useful because they minimize keystrokes. While minimizing keystrokes may seem to be a minor concern at first glance, an administrator who issues lengthy and complex command lines repeatedly may find these shortcuts a handy and necessary time-saving feature.
The following is a list of the IRIX metacharacters:
Table 2-1. IRIX Metacharacters
Metacharacter | Meaning |
|---|---|
* | wildcard |
? | single character wildcard |
[] | set definition marks |
The asterisk (*) metacharacter is a universal wildcard. This means that the shell interprets the character to mean any and all files. For example, the command:
cat * |
tells the shell to concatenate all the files in a directory, in alphabetical order by filename. The command:
rm * |
tells the shell to remove everything in the directory. Only files will be removed, though, since a different command, rmdir(1) is used to remove directories. However, the asterisk character does not always have to refer to whole files. It can be used to denote parts of files as well. For example, the command:
rm *.old |
will remove all files with the suffix.old on their names.
The single character wildcard is a question mark (?). This metacharacter is used to denote a wildcard character in one position. For example, if your directory contains the following files:
file1 file2 file3 file.different |
and you wish to remove file1, file2, and file3, but not file.different, you would use the command:
rm file? |
If you used an asterisk in place of the question mark, all your files would be removed, but since the question mark is a wildcard for a single space, your desired file is not chosen.
Square brackets denote members of a set. For example, consider the list of files used in the example of the single character wildcard. If you wanted to remove file1 and file2, but not file3 or file.different, you would use the following command:
rm file[12] |
This command tells the shell to remove any files with names starting with file and with the character 1 or 2 following, and no other characters in the name. Each character in the brackets is taken separately. Thus, if our example directory had included a file named file12, it would not have been removed by the above command. You can also use a dash (-) to indicate a span of characters. For example, to remove file1, file2, and file3, use the following command:
rm file[1-3] |
Alphabet characters can be spanned as well, in alphabetical order. The shell does pay attention to upper case and lower case letter, though, so to select all alphabet characters within square brackets, use the following syntax:
[a-z,A-Z] |
You can use the square brackets in combination with other metacharacters as well. For example, the command:
rm *[2,3] |
removes any files with names ending with a 2 or 3, but not file1 or file.different.
The IRIX C Shell (/bin/csh) provides several features that can be used to minimize keystrokes for routine tasks. Complete information about these and many other features of the C Shell is available in the csh(1) reference page. Among the features provided are:
| filename completion | set filec Filename completion allows you to enter the first character or two of a command or file name and then press the Escape key to have the shell complete the name. This is useful when you have long filenames with many suffixes. If more than one file or directory or command matches the characters you have given, the shell completes as much as possible of the name, and then prompts you with a beep for more information. You can also use the <Ctrl-D> character to select all files or directories that match your given characters. | |
| shell scripts | This feature allows you to create a program that will be executed by the shell. This feature is similar to a programming language in that it has a set syntax and set of instructions, yet it requires no compiler and produces no object file; it is directly executed by the shell. Many administrators use this feature for frequently performed procedures that require some planning and complex execution, such as finding large files and notifying the owners that such files cannot be kept on the system for long periods of time. The shell script programming rules are clearly presented on the csh(1) reference page. | |
| input/output redirection | ps -ef | grep commandname The pipe character directs the shell to use the output of the ps command as the input to the grep command. The result is that all instances of the command commandname in the process list are printed on the screen, saving the administrator the effort of searching through the process listing. | |
| job control | This feature allows you to use a single screen (or shell window) to manage several programs running simultaneously. It is most useful for the server administrator who manages the system from a single character-based terminal. | |
| command aliasing | ls -CF | more This command line executes the ls command with certain options and ensures that if the output is greater than a screenful it will be stopped until you have read it. However, it would be tedious to type the whole command each time you wanted to see a directory listing in your preferred format. Therefore, you should create an alias. You can alias the above command line to any series of keystrokes you like. You can even alias it to “ls,” thus bypassing the standard meaning of the ls command. When you create the alias, however, be aware that any command that requires one or more arguments, or one such as ls that may or may not receive arguments, must have a provision made in the alias for those arguments. The standard provision made in aliases for possible arguments is the following regular expression: \!* The leading backslash escapes the initial meaning of the exclamation point to the shell and passes the exclamation point through to the command line, where it is interpreted by the shell to refer to arguments given on the aliased command line. The asterisk in the expression means that all characters typed in as arguments are to be passed through to the shell. As an example, the line you place in your .cshrc file to create the example alias is: alias ls `ls -CF \!* | more` Then, when you type the command: ls filename at your shell prompt, the command is executed as: ls -CF filename | more Aliases can be used freely within shell scripts, with filename completion and full use of regular expressions and output redirection. | |
| command history | !! To execute the most recent command beginning with the letter “q,” use the command line: !q And to execute a command by its number in the history, give the command line: !n where n is the number of the previous command you wish to re-execute. |
The /usr/bin/tcsh program is an improved version of the C shell. In addition to the C shell features listed above, this shell offers many new features. A few of the most useful to system administrators are:
Better command line editing using emacs and vi key commands.
Improved history mechanisms, including time stamps for each command.
Built-in mechanisms for listing directory contents and for executing commands at specific times or intervals.
There are many more features implemented in Tcsh, and all of them are covered in the tcsh(1) reference page.
The Bourne shell (/bin/sh) provides fewer features than the C shell, but in its place offers a level of access to the shell that contains far fewer restrictions and intervening layers of interface. For example, you can write shell script programs directly from the shell prompt with Bourne shell. Input and output redirection and command aliasing are supported with the Bourne shell, but no command history, job control, or filename completions are available. For a complete discussion of the Bourne shell and its features, see the sh(1) reference page.
The Korn shell was developed to provide the best features of both the C shell and the Bourne shell. The /bin/ksh program provides the ease of shell programming found in the Bourne shell, along with the job control, history mechanism, filename completion, and other features found in the C shell. This shell has changed many of the ways these features are implemented, and also provides improved command line editing facilities. See the ksh(1) reference page for complete information on this shell. Useful features include:
| Emacs Editing | This mode is entered by enabling either the emacs or gmacs option. To edit, the user moves the cursor to the point needing correction and then inserts or deletes characters or words as needed as if the command line were a text file being edited using Emacs. All edit commands operate from any place on the line (not just at the beginning). | |
| vi Editing | To enter this mode, enable the vi option. There are two typing modes in this option. Initially, when you enter a command you are in the input mode. To edit, the user enters control mode by typing ESC, moves the cursor to the point needing correction, then inserts or deletes characters or words as needed as if the command line were a text file being edited using vi. | |
| job control | Lists information about each given process (job) or all active processes if the job argument is omitted. The -l flag lists process ID numbers in addition to the normal information. The -n flag only displays jobs that have stopped or exited since last notified. The -p flag causes only the process group to be listed. See the ksh(1) reference page for a description of the format of the job argument. The bg command puts each specified process into the background. The current process is put in the background if job is not specified. The fg command brings each process specified to the foreground. Otherwise, the current process is brought into the foreground. |
The following commands are provided by IRIX independent of any shell.
You can invoke a graphical utility or application on a remote networked workstation and direct the window and all input and output to your own local workstation if you desire. This is very convenient when you wish to perform maintenance on remote workstations from your own desk. The program you invoke will run on the remote workstation and the window will be displayed on the specified display workstation.
First, use rsh(1), rlogin(1), or telnet(1) to log in to the remote workstation with whatever privilege level is required to perform the maintenance on that system. In some cases, this may be as simple as the guest account, or you may have your own user account on the system, or you may require root permission. Choose the level of access appropriate to your task. Then, issue the command:
setenv DISPLAY local_workstation:0 |
The name of the workstation where the window is to be displayed is substituted for local_workstation. The name of the local workstation must be found in the /etc/hosts file of the remote system, where the program is actually running.
Next, invoke the desired utility or application on the remote system and the window will display on your local workstation. All input and output will be handled through your local workstation. Remember that due to restrictions of network carrying capacity, response time in the program may be slower (in some cases, much slower) than usual.
When you are finished, exit the display program normally. You must also reset the display on the remote station, or all susequent window applications will continue to appear on the local workstation. On the remote system, use the command
setenv DISPLAY :0 |
to reset the display back to the remote system monitor.
IRIX allows you to create a shell window using any colors you like from the palette on your graphics workstation. You may also select any font you prefer from the font set on your system. The xwsh(1) command creates the shell window, and the options to this command control the various fonts, colors, and other features available to you. The command shell used in the window is taken by default from your /etc/passwd file entry or it can be specified on the command line according to the instructions in the xwsh reference page.
For a complete list of the features available with xwsh(1), see the xwsh reference page. The most commonly used features are described here in the following examples.
To create a simple shell window with a dark gray background and yellow text, issue the following command:
xwsh -fg yellow -bg gray40 & |
The above command generates a new window and a new shell using the colors specified. The window will use the default font selection and window size, since these attributes were not specified. The command that created the shell was placed in the background, so the shell does not tie up the window where you gave the command. You can always place a command in the background by adding the ampersand character (&) to the end of the command line. For more information on placing processes in the background, see the csh(1) reference page.
There are 100 shades of gray available. Gray0 is the darkest, and is virtually black. Gray100 is the lightest and is virtually white. The effect of selecting foreground (text) in yellow and background in gray40 is similar to yellow chalk on a gray chalkboard. For a complete list of the available colors in your palette, use the colorview(1) command. This brings up a window with the list of colors in a scrollable list, and a display window to show a patch of the currently selected color.
In the next example, we change the colors to black on a sky blue background (high contrast between the foreground and background makes reading the screen easier), and we add a specification for the size of the window.
xwsh -fg black -bg skyblue -geometry 80x40 & |
The first number in the geometry option is 80, indicating that the new shell window should be 80 characters wide (this is the default). The second number indicates the desired number of lines on the screen, in this case 40. Once again, the xwsh command has been placed in the background by adding the ampersand character to the end of the command line.
You can make your new shell come up on your desktop as an icon by adding the -iconic flag to any xwsh command.
To select a font other than the default, you can use the on-screen font selection utility, or you can specify the font on the command line. It is a great deal easier to use the on-screen font selection utility, as you must specify a great number of attributes for the font on the command line. Also, it frequently takes a great number of selections before you settle on a font, a weight (regular or bold, condensed or normal) and a font size that appeals to you. Using the on-screen font utility, you can preview what each selection will look like on your windows.
Once you have made your selections, you can copy and paste the font selection information and the rest of your xwsh command into a shell script file for convenient future use. For example, here is an xwsh command line that specifies the IRIS-specific font haebfix in a medium weight with normal spacing, 15 pixels tall. The remaining information is generated by the font selection utility for the shell.
xwsh -iconic -fg yellow -bg grey40 -geometry 80x40 -fn \ -sgi-haebfix-medium-r-normal--15-150-72-72-m-90-iso8859-1 & |
Note that in your shell script, the above command appears all on one line. Due to formatting constraints, the command is broken across two lines in this example.
For complete information on using the font selection utility in xwsh and the xfontsel(1) command, see Chapter 2 of the IRIS Utilities Guide.
The IRIX system provides several tools for manipulating large numbers of files quickly. Some of the most common are described below:
The find(1) utility locates files and can invoke other commands to manipulate them.
The sed(1) program edits files using pre-determined commands.
Many other programs have recursive options, with which you can quickly operate on files that are in many levels of subdirectories.
The find(1) command is used to find files and possibly execute commands on the files found. It starts at a given directory and searches all directories below the starting directory for the specified files. A basic find command line looks like this:
find . -name <filename> -print |
This command searches the current directory and all subdirectories downward from the current directory until it finds all matches to the <filename> and then displays their locations on your screen. You can also use regular expressions (see “Using Regular Expressions and Metacharacters”) in your searches.
The following command line searches for files that have been changed after the time /tmp/file was last modified. If you use touch(1) to create /tmp/file with an old date, this command can help you find all files changed after that date.
find / -local -newer /tmp/file -print |
You can use find to locate files and then to run another command on the found files. This example shows how to locate a file in a user's directory:
cd /usr/people/trixie find . -name 'missingfile' -print |
In this example, the period (.) indicates the current directory, the -name option indicates that the next argument in quotes is the name of the file you are looking for, and the -print option tells find to display the pathname of the file when the file is located.
The next example shows how to change the permissions on all the files in the current directory and in all subdirectories:
find . -name '*' -local -exec chmod 644 {} \;
|
The option immediately following the find command is a period (.). This indicates to find that the search is to begin in the current directory and include all directories below the current one. The next flag, -name, indicates the name of the files that are being found. In this case, all files in the directory structure are selected through the use of the asterisk metacharacter (*). See “Using Regular Expressions and Metacharacters” for more information on metacharacters and regular expressions.
The -local option indicates to find that the search is limited to files that physically reside in the directory structure. This eliminates files and directories that are mounted via the Network File System (NFS). The -exec option causes find to execute the next argument as a command, in this case chmod 644. The braces, { }, refer to the current file that find is examining.
The last two characters in the command line are part of the chmod command that will be executed (with the -exec option) on all files that match the search parameters. The backslash (\) is necessary to keep the shell from interpreting the semicolon (;). The semicolon must be passed along to the chmod process. The semicolon indicates a carriage return in the chmod command.
The find command has several other useful options:
| -inum n | Locate files by their inode number (n) instead of their name. | |
| -mtime n | Identify files that haven't been modified within a certain amount of time (n). | |
| -perm [-]||onum |
If you place a minus sign in front of onum, only the bits that are actually set in onum are compared with the file permission flags. | |
| -type x | Identifies files by type, where x specifies the type. Types can be b, c, d, l, p, f, or s for block special file, character special file, directory, symbolic link, FIFO (a named pipe), plain file, or socket respectively. | |
| -links n | Matches files that have n number of links. | |
| -user uname | Identifies files that belong to the user uname. If uname is a number and does not appear as a login name in the file /etc/passwd, it is interpreted as a user ID. | |
| -group gname | Identifies files that belong to the group gname. If gname is a number and does not appear in the file /etc/group, it is interpreted as a group ID. | |
| -size n [c] | Identifies files that are n blocks long (512 bytes per block). If you place a c after the n, the size is in characters. | |
| -ok cmd | Works like -exec, except a question mark (?) prompts you to indicate whether you want the command (cmd) to operate on the file that is found. This is useful for such operations as selectively removing files. |
The find and cpio commands can be used to easily and safely copy a directory or a directory hierarchy as long as the user has permissions to access the directory. To copy a directory with all its files, or an entire hierarchy of directories and their files, use commands like the following:
mkdir new_directory_name cd the_directory_you_want_to_copy find . -print | cpio -pdlmv new_directory_name |
This command sequence preserves the symbolic links in the new directory as well as transparently cross file system boundaries.
You can use sed(1), the Stream Editor, to automate file editing. The sed command follows an editing script that defines changes to be made to text in a file. The sed command takes a file (or files), performs the changes as defined in the editing script, and sends the modified file to the standard output. This command is fully described in the IRIX Development Option documentation and in the sed(1) reference page, which is included in your IRIX distribution. The IRIX Development Option is available for separate purchase from Silicon Graphics.
Recursive commands can save you a lot of time. For example, to change the ownership of all the files and directories in a directory recursively, and all of the files and directories in all of the subdirectories below that, you can use the recursive option with chown(1):
chown -R username directory |
Some of the other commands in the IRIX system that have recursive options are:
ls -R rm -r chgrp -R |
If you want to use a particular command recursively, but it does not have a recursive option, you can run the command using find. See “Using find to Locate Files”.
Note that using recursive options to commands can be very dangerous in that the command automatically makes changes to your files and file system without prompting you in each case. The chgrp command can also recursively operate up the file system tree as well as down. Unless you are sure that each and every case where the recursive command will perform an action is desired, it is better to perform the actions individually. Similarly, it is good practice to avoid the use of metacharacters (described in “Using Regular Expressions and Metacharacters”) in combination with recursive commands.
You can use the at(1), batch(1), and cron(1M) utilities to automate many of your usual tasks, both as an administrator and as a user. These utilities perform similar functions. All execute commands at a later point in time. The difference between the commands is that at executes the given command at one specific time; cron sets up a schedule and executes the command or commands as often as directed, according to the schedule; and batch executes the commands when system load levels permit the execution.
If you have a task to process once at a later point in time, use at. For example, if you wish to close down permissions on a public directory at midnight of the current day, but you do not need to be present when this occurs, you could use the command string:
at 2400 July 14 chmod 000 /usr/public <Ctrl-D> |
It is required that the at command itself and the date and time of the command be placed alone on a line. When you press <Return>, you do not see a prompt; at is waiting for input. Enter the command to be executed just as you would type it at a shell prompt. After entering the command, press <Return> again and enter <Ctrl-D> to tell at that no more commands are forthcoming. You can use a single at command to execute several commands at the appointed time. For example, if you want to close the public directory and change the message of the day to reflect this closure, you can create the new message of the day in the file /tmp/newmesg, and then issue the following command string:
at 2400 July 14 chmod 000 /usr/public mv /etc/motd /etc/oldmotd mv /tmp/newmesg /etc/motd <Ctrl-D> |
By default, any output of commands executed using at is mailed to the executing user through the system electronic mail. You can specify a different location for the disposition of output by using the standard output redirects, such as pipes (|) and file redirects (>). See your command shell documentation for a complete description of redirecting the standard output.
For complete information on the at command, see the at(1) reference page.
The batch command works just like the at command, except that you do not specify a time for the command or commands to be executed. The system determines when the overall load is low enough to execute the commands, and then does so. As with all other cron subsystem commands, the output of the commands is mailed to you unless you specify otherwise. batch is useful for large CPU-intensive jobs that slow down the system or cripple it during peak periods. If the job can wait until a non-peak time, you can place it on the batch queue until the system executes it. For complete information on the batch command, see the batch(1) reference page.
If you desire to have a command executed regularly on schedule, the cron command and subsystem provide a precise mechanism for scheduled jobs. The at and batch commands are technically part of the cron subsystem and use cron to accomplish their tasks. The cron command itself, though, is the most configurable command of the subsystem.
You use cron by setting up a crontab file, where you list the commands you would like to have executed and the schedule for their execution. Complete information on setting up your crontab file is available in the cron(1M) and crontab(1) reference pages.
The cron facility is useful for scheduling network backups, checking the integrity of the password file, and any other scheduled tasks that do not require interaction between you and the system. By default, cron mails the results or output of the command to the user who submitted the crontabs file, so if you use cron to schedule something like a pwck(1M), the results of the test are mailed to you and you can interpret them at your convenience.
Note that you must restart cron after each change to a crontabs file, whether made through the cron utility or the at command, for the changes to take effect.
The /etc/nologin file prevents any user from logging in. This feature of the login(1) program is designed to allow the system administrator to have the system running in full multiuser mode, but with no users logged in. This is useful when you wish to perform complete backups of the system or when you want to do some testing that may cause the operating system to halt unexpectedly. Of course, it is always best to do this sort of work during non-peak system usage hours.
To disable logins, simply create a file called nologin in the /etc directory. (You must be logged in as root to create files in /etc.) In addition to disallowing logins, the login program will display the contents of /etc/nologin when it denies access to the user. To allow logins again, simply remove the /etc/nologin file. A suggested format for the message in /etc/nologin is:
The system is unavailable for a few moments while we perform some routine maintenance. We will be done shortly and regret any inconvenience this may cause you. -Norton |
The system hardware for graphical workstations (and some X-terminals) can provide you with shortcuts. These may not be available to server administrators who rely solely on character-based terminals for their administration. Using the graphics console of your system, you can cut and paste between windows without using pull-down or pop-up menus of any sort. Using the pop-up menu, you can manipulate your windows completely.
Note that you can customize the action of your mouse buttons. All examples in this section assume the default mouse button meanings are being used. If you have modified your mouse action, you must allow for that modification before you use these techniques.
For complete information on using the pop-up windows, see your IRIS Essentials book, either in hard copy or on screen through the IRIS InSight software package.
The most common mouse shortcut is to cut, copy, and paste between windows on your screen. Here is how you do it:
Find the cursor controlled by your mouse on your screen. It should appear as a small arrow when it is positioned in the working area of one of your windows, or as an “X” when it is positioned on your background screen, or as some other figure when it is positioned on the frame of a window or in the working area of an application's window. If you can't locate the cursor immediately, move the mouse around a bit and look for motion on your screen. You should find the cursor easily.
Place the cursor at the beginning of the text you wish to paste between windows and press the leftmost key on the top of the mouse. Now, keeping the mouse button depressed, move the cursor to the end of the text you wish to paste. The intervening area of the window changes color to show the selected text. If you are selecting a large section of text, it is not necessary to move the cursor over every space. You may move the cursor directly to the end point and all intervening text will be selected. It is not possible to select “columns” of text or several disconnected pieces of text at once. When you have moved the cursor to the desired end point, release the mouse button. The text remains highlighted.
Now move the cursor to the window you want to paste the text into and make certain the window is ready to receive the pasted text. For example, if you are pasting a long command line, make certain that there is a shell prompt waiting with no other command already typed in. If the pasted matter is text into a file, make certain that the receiving file has been opened with an editor and that the editor is in a mode where text can be inserted.
To paste the text, place the cursor in the receiving window and press the middle mouse button once quickly. Each time you press the middle button, the selected text will be pasted into the receiving window. Sometimes it takes a moment for the text to appear, so be patient. If you press the button several times before the text appears, you will paste several copies of your text.
You can also paste your selected text to the bottom of a window (including the window from which you selected the text). Press the rightmost mouse button while the cursor is in that window and select the send option from the pop-up menu that appears.
The text you originally selected remains selected until you select new text somewhere else or until you place the cursor back in the original window and click once on the leftmost mouse button.
If you need a new shell window, you can use the mouse to create one. Follow these steps:
With the cursor in a shell window, press the rightmost button on your mouse. A pop-up menu appears:
The last item on the pop-up menu is the clone option. There is a small triangle to the right of this option. This triangle indicates that there are more sub-choices available in another pop-up menu. While keeping the button on the mouse depressed, move the mouse down until the clone option is highlighted and the sub-menu pops up, showing various shell window cloning options. These options create another shell window functionally identical to the one in use. This is why the option is called cloning. The text and background colors of the current window are carried forward to the cloned window, and the selections in the sub-menu specify the number of lines in the new window. You can choose to have the same number of lines in the cloned window as in the current window, or to have 24, 40, or 60 lines.
Select the size you want by moving the mouse down to highlight each option and releasing the mouse button when the option you desire is highlighted. The new window will appear on your screen presently. You may repeat this process as often as you like on any shell window.
Reference pages are online reference manual entries. A full set of reference pages for the programs, utilities, and files in the standard IRIX distribution is provided on-line, and these pages are available through the man(1) command. In addition, you can create your own custom reference pages using the following procedure. Any time you create a script, utility, program, or application for your users, you should also create a reference page. This provides a convenient way for your users to learn to use your new tools, and also makes future maintenance easier.
Not all sites will have the optional Documenter's Workbench software product installed, but you can create a facsimile of a reference page using only the text editor of your choice. See the following section for details.
 | Note: To create a pure-text reference page without Documenter's Workbench (no embedded nroff(1) commands that would format the text) simply use the vi editor (or the editor of your choice) and document your script or program according to the style found in the standard reference pages. Name your reference page file after the script or program it documents with the suffix ``.l'' at the end of the file name to designate the page as a local reference page. |
| Note: Use the letter “l” as your suffix, not the numeral one “1.” |
When you have completed your reference page, you must place it in the /usr/man directory structure for the man(1) command to be able to display the new page. Place the reference pages in a local directory, such as /usr/man/manl. (Again using the character ``l'' to designate local reference pages.) If it does not already exist, create the directory with this command (you must be logged in as root):
mkdir /usr/man/manl |
Long reference pages should be packed to save disk space. Use the pack(1) command to pack the text file into a more compact form. For example:
pack program.1 mv program.1.z /usr/man/manl/program.z |
| Note: The man program automatically unpacks the pages for reading. |
IRIX provides a set of detailed programs for use in assisting you and your customer support provider in debugging potential system problems. This software is briefly described here. Complete documentation is available in the relevant reference pages and through the help system files and release notes distributed with the software. The savecore, icrash, fru, and sysmon software works together to provide a picture of what happens to your system in an error condition that results in an operating system crash.
Your system does not automatically save the image of system memory at each system crash. When the system does store such an image, it is stored in a file called /var/adm/crash/vmcore.N, where N is a sequential number assigned to the most recent core file. The savecore command has a chkconfig option that can be turned on or off depending on your needs. Here is what happens under the two possible conditions:
| savecore is on | The system saves the core dump. When the core dump has been saved, if a dump is successful, it will then run icrash on the core dumps that have been saved. | |
| savecore is off | A core dump will not be saved by the system; however, icrash is still run on /unix and /dev/swap in order to get a report of what happened when the machine crashed. In this case, systems do not have to use the disk space on a core dump in order to get a report. |
Two report files are created when icrash runs, with N being the bounds number for the core dump:
| analysis.N | An analysis of the core dump is created containing items of interest, such as the putbuf dump, fru information, stack traces, and so on. This is a verbose description of what happened when the system crashed, and it is meant to be used to perform a preliminary analysis of the system before any hardware or software changes are made. See the icrash(1M) reference page for more information. | |
| summary.N | The summary report contains the panic string, the crash time, and the fru information in one file for availmon. See the availmon(1M) reference page for more information. |
The icrash(1M) utility interactively generates detailed kernel information in an easy-to-read format. The icrash command also provides the ability to generate reports about system crash dumps created by savecore(1).
Depending on the type of system crash dump, icrash can create a unique report that contains information about what happened when the system crashed. The icrash command can be run on both live systems or with any namelist file and core file specified on the command line. The namelist file must contain symbol table information needed for symbolic access to the system memory image being examined.
Each version of icrash is specific to the OS release that it came from, and will not work on any other OS release. Do not copy icrash to any other IRIX system unless the OS versions are identical (including patch levels). Running icrash on a live system can sometimes generate random results, as the information being viewed is volatile at the time it is displayed.
A brief list of some of the functionality that icrash offers:
System crash reports created on system panics
Field replacement unit (FRU) information provided with each crash on eligible hardware
Direct access to a broad list of kernel structures
Disassembly of kernel functions
Documented set of commands (see the help system within icrash)
Command line editing and history
The fru (Field Replacement Unit) command (described fully in the fru(1M) reference page) displays field replacement unit analysis on Challenge L and XL, Onyx L and XL, and Power Challenge and Power Onyx systems only. The program considers the hardware state during an error situation and attempts to determine if the error results from faulty hardware. The analysis is based on the hardware error state created in the kernel crash dump. If no hardware error state is dumped, no fru analysis will be displayed.
Each board will be analyzed separately based on the hardware error state. After the analysis is completed, the board (or boards) with the highest confidence levels will be displayed. Currently the boards analyzed include the IO4, MC3, IP19, and IP21. Note that you should also check the version of fru output from release to release, because later versions may report a different analysis.
When a confidence level is displayed, it is based on the amount of confidence that the fru analyzer has in the board listed as being the problem. Note that there are only a few levels of confidence, and it is important to recognize what the percentages mean:
| 10% | The board was witnessed in the hardware error state only. | |
| 30% | The board has a possible error, with a low likelihood. | |
| 40% | The board has a possible error, with a medium likelihood. | |
| 70% | The board has a probable error, with a high likelihood. | |
| 90% | The board is a definite problem. | |
| 95% | The board is a definite problem, an exact error match. |
There is a possibility of multiple boards being reported, so the field engineer must be cautous when deciding to replace boards. For example, if two boards are reported at 10%, that is not enough confidence that the boards listed are bad. If there is one board at 70% or better, there is a good likelihood that the board listed is a problem, and should be replaced. Boards at 30% to 40% are questionable, and should be reviewed based on the frequency of the failure of the specific board (in the same slot) between system crashes.
The objective is to uncover real hardware problems, rather than to replace boards at random. Each icrash report for each kernel core dump on an eligible system will have a fru analysis in it, which should be reviewed by field engineers before any boards are replaced.
Below are some fru output examples. Please note that each fru command output below comes from a unique core dump. Your output is likely to vary significantly:
>> fru FRU ANALYZER (2.0.1): ++ PROCESSOR BOARD ++ IP21 board in slot 2: 40% confidence. ++ END OF ANALYSIS >> fru FRU ANALYZER (1.6.5): ++ MEMORY BOARD ++ MC3 board in slot 1: 70% confidence. ++ END OF ANALYSIS >> fru FRU ANALYZER (1.6.5): ++ CPU slice 3 (CC CHIP) ++ and/or Integral component (A CHIP) ++ on the IP19 board in slot 5: 40% confidence. ++ CPU slice 3 (CC CHIP) ++ and/or Integral component (A CHIP) ++ on the IP19 board in slot 7: 40% confidence. ++ CPU slice 2 (CC CHIP) ++ and/or Integral component (A CHIP) ++ on the IP19 board in slot 9: 40% confidence. ++ CPU slice 3 (CC CHIP) ++ and/or Integral component (A CHIP) ++ on the IP19 board in slot 11: 40% confidence. ++ END OF ANALYSIS >> fru FRU ANALYZER (2.0.1): No errors found. |
The sysmon utility is part of the Desktop System Monitor. It can be launched from the toolchest's System menu by selecting “View System Log.” You see a window similar to that shown in Figure 2-3:
You can select View, Filter and Sort options through the pull-down menus on this window. Your selections are saved in your $HOME/.sysmonrc file. For additional information on these options, please consult the on-line help available through this window or the sysmon Release Notes.
The sysmon utility allows a user to browse the system log file (/var/adm/SYSLOG). The 8 SYSLOG priorities (see the syslog(3B) reference page) are simplified into 4 priority levels.
The following table shows how SYSLOG priorities map into the sysmon simplifed priority scheme:
Table 2-2. The sysmon Priority Table
sysmon Priority | SYSLOG Priority | Numerical Priority |
|---|---|---|
CRITICAL | LOG_EMERG | 0 |
CRITICAL | LOG_ALERT | 1 |
ERROR | LOG_CRIT | 2 |
ERROR | LOG_ERR | 3 |
WARNING | LOG_WARNING | 4 |
WARNING | LOG_NOTICE | 5 |
INFO | LOG_INFO | 6 |
INFO | LOG_DEBUG | 7 |
The availability monitor (described completely in the availmon(5) reference page) is a software package that together with icrash and the FRU analyzer, provides a technology platform for system availability and diagnostic data gathering and distribution.
The availmon system collects system availability information and crash diagnosis information. The availability information can be used to evaluate system reliability and availability. The crash diagnosis information is an automated aid to debugging.
The availmon software is embedded in the system boot and shutdown processes. The software is capable of differentiating controlled shutdowns, system panics, system hangs, power cycles, and power failures. Your system's uptime is estimated by a daemon process, and diagnostic information is collected from icrash(1M), /usr/adm/SYSLOG and sysmon(1M), hinv(1M), versions(1M), and gfxinfo(1G). All aspects of availmon operation are fully configurable.
You can choose to participate in a system availability database that assists Silicon Graphics support in providing reliable service. All availability and diagnostic data for cooperating systems will be maintained in an SGI database. Access to that database provides overall reliability data, and specific histories for individual participating systems. This is the primary function of availmon.
You must issue the amregister command to set up availmon configuration, turn on autoemail, and register your system with the Silicon Graphics Availmon Database.
To register your system, log in as root and issue the command:
/usr/etc/amregister -r |
Depending on your system type, you may need to enter the serial number of your system by hand. See the amregister(1M) reference page for further information.
The availmon software is enabled through the chkconfig(1M) command, described in “Checking Options With chkconfig”. The flags are:
| availmon | Controls the activation of the entire availmon software package. By default, this option is on. |
The other configuration flags are set using the amconfig(1M) utility, which is similar to chkconfig, but uses a different record file. There are four flags:
| autoemail | Enables automatic distribution of reports. By default, this option is off, but is turned on by amregister. | |
| hinvupdate | Enables a daemon that checks for changes reported by hinv and gfxinfo. By default, this option is on for large systems and off for all others. | |
| shutdownreason |
| |
| tickerd | Enables the daemon that monitors system uptime. By default, this option is on for large systems and off for all others. |
There is also an e-mail list configuration file, /var/adm/avail/config/autoemail.list, used to control the report type, e-mail format, and e-mail addresses for availmon reports. The e-mail list is edited and maintained through the amconfig(1M) command. By default, this file is configured to send diagnosis reports to Silicon Graphics.
For sites with multiple systems participating, the amconfig command can be executed on one system to set up a common email configuration file (/var/adm/avail/autoemail.list), and then this file can be copied onto all participating systems. Then run amregister -r on each system.
If a site log file for one or more systems is desired, a pseudo e-mail alias can be created. This alias pipes availability reports to amreceive whose output is then appended to the site log file. This procedure should be done before registering all the systems, because initial availability reports will be sent out when registering.
After setting up availmon, amreport can be executed on each system to view the availability statistics and reports for that system, or it can be run with the site log file as input to view overall availability statistics for all systems, and availability reports for any system.
If a site log file is desired, perform the following steps in order:
Create an e-mail alias on one system and pipe all availability reports to amreceive. For example, if the site logfile is to be /disk/amrlog, add this line to the mail server system's /etc/aliases file:
amrlog: “| /var/adm/avail/amreceive >> /disk/amrlog”
and then run the newaliases command to set up this e-mail alias.
Then, run the amconfig command on the mail server system to configure the standard e-mail lists. For our example log file, add the entry:
availability(text): amrlog
Then, copy the resulting /var/adm/avail/config/autoemail.list on this system to the rest of the systems at your site.
Run amregister to register all your systems as described above in “Registering and Configuring availmon”.
Now the command:
amreport -s /disk/amrlog
shows the overall statistics, system statistics, and individual availability reports for all participating systems.
Three examples are provided to illustrate the administration of availmon. One is for general customers that send reports out automatically; the other two are for secure sites with and without internal report sending.
If availmon is installed on a single system, reboot the system after installation. Then, run amregister without any argument to register and configure the e-mail lists. This will turn on autoemail and send registration reports to all configured addresses when complete. If your system does not have an IP19, IP21, IP22, or IP25 processor, amregister prompts you to input your system's serial number manually.
The shutdownreason and tickerd configuration options can be turned on or off anytime. The default autoemail.list is:
availability(compressed,encrypted): availability(compressed): availability(text): diagnosis(compressed,encrypted): availmon@csd.sgi.com diagnosis(compressed): diagnosis(text): |
In addition, you may want to add the following entries:
availability(text): <local_sysadmin> diagnosis(compressed,encrypted): <local_support> |
In the above optional entries, replace the strings <local_sysadmin> and <local_support> with the appropriate e-mail addresses for your system administrator and Silicon Graphics support representative, respectively.
If encrypted data in email is prohibited by law at your site, move addresses in “(compressed,encrypted)” entries to “(compressed)” entries.
If your site is under security restrictions, you may use the following procedures to set up and use availmon. The setup procedure is similar to that found in “Registering and Configuring availmon”, except that the addresses outside your site should be deleted.
After your system administrators receive availmon reports, they can check the latest diagnosis report, /var/adm/crash/diagreport on the system just rebooted, delete any sensitive data and use amsend to mail the filtered report to availmon@csd.sgi.com and any Silicon Graphics support address they require. If the diagnosis report contains any ICRASH, SYSLOG, HINV, VERSIONS, or GFXINFO data, use the command:
amsend -i -z -x availmon@csd.sgi.com ... |
to mail the report. If there is no such data in the report, use the command:
amsend -d -z -x availmon@csd.sgi.com ... |
If encrypted data in e-mail is prohibited by law at your site, remove -x from the command line.
If outisde report mailing is not possible at your site, no special actions need to be taken to use availmon. However, for those platforms not using IP19, IP21, IP22, and IP25 processors, amregister should still be run and then you should turn off autoemail so that reports generated on these systems will not be sent automatically. The shutdownreason and tickerd options can also be turned on or off as you choose.
Since no external report is mailed after the system reboots, system administrators need to check if the system has been down, and then check the report files to determine the reason. If the system crashes more than once before checking, old reports will be overwritten by the new ones (core dumps and icrash reports will be kept until removed explicitly). Therefore, internal report mailing is recommended for secure sites.
Diagnosis reports can be sent to Silicon Graphics using amsend. See the section titled “Using availmon at Secure Sites with Internal Report Mailing”. Another method is to run amconfig to configure standard e-mail lists so that when reports need to be sent, amnotify can be used to send reports according to those lists.
There are two types of reports produced by availmon: availability and diagnosis. Availability reports consist of system start time, stop time, stop reason, uptime, re-start time, and a summary of the likely reason for any system crash (where relevant). A standard availability report is shown here:
------------------------------ whizkid ---------------------------- Report Version ......... 0.1 Internet Address ....... whizkid Reason for Shutdown .... Hang Started at ............. Mon Oct 3 16:56:08 1994 Stopped at ............. Unknown instant Uptime ................. 4304 minutes (2 days 23 hrs 44 mins) ------------------------------------------------------------------- Press <enter> to display summary ... |
When you press <Enter>, you see information similar to the following:
======================= SUMMARY for whizkid ========================== Controlled Shutdowns ... 0 Hangs .................. 1 Panics ................. 0 Average Uptime ......... 2189 minutes (1 day 12 hrs 29 mins) Least Uptime ........... 74 minutes (1 hr 14 mins) (*) Most Uptime ............ 4304 minutes (2 days 23 hrs 44 mins) Availability ........... 0.7870% Logging started at ..... Mon Oct 3 16:56:08 1994 System has been up for . 74 minutes (1 hr 14 mins) Last boot at ........... Tue Oct 24 23:03:44 1995 ====================================================================== |
Diagnosis reports additionally contain icrash analysis report (including the FRU analyzer result), important syslog messages, and system hardware/software configuration and version information.
Availability information is permanently stored in /var/adm/avail/availlog. Files in /var/adm/avail are maintained by availmon and should not be deleted, modified, or moved. The most recent availability and diagnostic reports are stored in /var/adm/crash/availreport and /var/adm/crash/diagreport, and should be treated comparably to core dumps.
There are two ways to configure the sending of availmon reports: automatic or manual. If you select automatic mailing, you can configure any number of recipients for each type of report. The recommended configuration is to send diagnosis reports to the Silicon Graphics Availmon Database. Also, send diagnosis reports to Silicon Graphics Field Service and availability reports to your local system administration team. You can also send copies of all reports to a local log accoun. If you select manual mailing, the two types of reports are created in the directory /var/adm/crash. You can then edit or filter the reports, and then use the amsend command to send the approved reports.
The availmon software can be configured to compress and encode data. The receiving agent (using the amreceive command) decodes, uncompresses, and stores the data in a database at Silicon Graphics. Data encryption is recommended if it is not prohibited at your site.
The amreport(1M) utility is provided to review availmon reports and to provide statistical availability information. This program can process local availability log files or received aggregate availability reports (such as a site log file) from different systems.
The amreport utility shows the statistical reports and availability reports hierarchically from overall statistics for all systems, a table of statistics for all systems (however, if the input is a local log file, the above information is not provided), statistics for each system, a table of all reboot instances for each system, and availability reports for each system. See the amreport reference page for full information on this utility.