What is SMIT?
The System Management Interface Tool (more commonly known as SMIT)
is an interactive tool bundled with AIX®. Virtually any system
administration-related task can be completed using a SMIT screen; the
screens are logically grouped in a hierarchal manner for easy
navigation. Fast paths associated with every function can be used to go directly to the relevant screen.
One of the best features of SMIT is that you can see exactly what
commands it performs either before or after it runs those commands. SMIT
doesn't use any special hooks into the operating system.
Everything it does, it does through standard AIX commands and Korn shell
functions. This feature is especially useful when you need to automate a
repetitive task; you can have SMIT create the proper command-line
sequence, and you can then use those commands in your own script.
Basic usage
SMIT is part of the base operating system; the actual
/usr/bin/smit command
is in the bos.sysmgt.smit fileset. There are actually two versions of
SMIT: a full-screen text-mode version and a graphical X Windows® client.
If the DISPLAY variable is set, AIX automatically runs the GUI version.
To use the text-mode version -- even if your DISPLAY variable is set --
run the smittycommand , or you can run smit -a.
When SMIT is started without a fast path specified, the main menu is
displayed. In all SMIT screens, the arrow keys are used to move up and
down through the choices displayed. The Return key selects the currently
highlighted item. To go back one level, press F3 or Esc + 3.
The four screen types
There are four types of screens that SMIT uses to interact with and
display information to the user: menus, dialogs, selectors, and command
status screens.
Menus
A menu screen displays a list of tasks, only one of which
can be selected. When no fast path exists at SMIT startup, the main menu
is displayed (see Listing 1 for the text-mode version).
Listing 1. The main System Management screen, as seen in the text-mode version of SMIT
System Management
Move cursor to desired item and press Enter.
Software Installation and Maintenance
Software License Management
Devices
System Storage Management (Physical & Logical Storage)
Security & Users
Communications Applications and Services
Print Spooling
Problem Determination
Performance & Resource Scheduling
System Environments
Processes & Subsystems
Applications
Installation Assistant
Using SMIT (information only)
F1=Help F2=Refresh F3=Cancel F8=Image
F9=Shell F10=Exit Enter=Do
Figure 1 shows SMIT's main menu in the GUI version of the tool.
Figure 1. The main System Management screen, as seen in the GUI version of SMIT
Dialogs
A dialog screen results from the selection of a specific task.
Various symbols indicate the type of information entry that each field
accepts. The data that you enter into those fields are used to form the
command that SMIT executes.
Listing 2. A SMIT dialog screen. Specifically, the Change/Show Characteristics of a User screen
Change / Show Characteristics of a User Type or select values in entry fields. Press Enter AFTER making all desired changes. [TOP] [Entry Fields] * User NAME root User ID [0] # ADMINISTRATIVE USER? true + Primary GROUP [system] + Group SET [system,bin,sys,securi> + ADMINISTRATIVE GROUPS [] + ROLES [] + Another user can SU TO USER? true + SU GROUPS [ALL] + HOME directory [/] Initial PROGRAM [/usr/bin/ksh] User INFORMATION [palatino root] EXPIRATION date (MMDDhhmmyy) [0] [MORE...37] F1=Help F2=Refresh F3=Cancel F4=List F5=Reset F6=Command F7=Edit F8=Image F9=Shell F10=Exit Enter=Do
Selectors
A select screen requires the user to choose a target, usually a
device that will be used in the subsequent dialog screen. Selectors
usually appear as a pop-up window, overlaying the text from the previous screen.
Listing 3. A SMIT select screen, requesting the selection of a single Logical Volume
LOGICAL VOLUME name
Move cursor to desired item and press Enter. Use arrow keys to scroll.
[TOP]
fslv00 jfs 64 128 2 open/syncd /ora-dat
fslv01 jfs 64 128 2 open/syncd /u06
fslv02 jfs 64 128 2 open/syncd /u07
lv07 jfs 11 22 2 open/syncd /SUL_ora
paging05 paging 32 32 1 open/syncd N/A
fslv05 jfs 320 640 4 open/syncd /u08
fslv06 jfs 24 48 2 open/syncd /w01
fslv07 jfs 16 32 4 open/syncd /local/a
lv11 jfs2 128 128 1 open/syncd /mkcd/mk
fslv09 jfs 128 256 2 open/syncd /u02
[MORE...51]
F1=Help F2=Refresh F3=Cancel
Esc+8=Image Esc+0=Exit Enter=Do
/=Find n=Find Next
Command Status
The Command Status screen displays the output from the commands that SMIT executed. The top of the screen indicates the current status (Running, OK, or Failed), and it also shows whether there was anything written to STDOUT or STDERR.
Listing 4. A SMIT Command Status screen, displaying the output of the List Fileset Containing File
COMMAND STATUS
Command: OK stdout: yes stderr: no
Before command completion, additional instructions may appear below.
File Fileset Type
------------------------------------------------------------------
/usr/bin/smit bos.sysmgt.smit File
F1=Help F2=Refresh F3=Cancel Esc+6=Command
Esc+8=Image Esc+9=Shell Esc+0=Exit /=Find
n=Find Next
Navigation
Because of the hierarchal nature of SMIT's functions, it is fairly simple to drill down into the task you wish to accomplish. If you find that you've selected the wrong item from a menu, pressing F3 (or Esc + 3) brings you back to the previous screen.
Every menu and dialog screen in SMIT has a fast path that can be
used to go directly to that screen. To determine the fast path for a
particular screen, navigate to that screen, and then press F8 or Esc + 8. A pop-up window lists the fast path and puts a print of the current screen into the SMIT log file.
Listing 5. A SMIT select screen, requesting the selection of a single Logical Volume
PRINT SCREEN
Press Enter to save the screen image
in the log file.
Press Cancel to return to the application.
Current fast path:
"mkuser"
F1=Help F2=Refresh F3=Cancel
Esc+8=Image Esc+0=Exit Enter=Do
Shortcuts
SMIT has several key commands that can be used to quickly navigate
through long, scrolling screens of output. While most useful in Command
Status screens, these keystrokes work in all screens (see Table 1).
Table 1. Key command for navigation
| Keystroke | Action |
|---|---|
| Down arrow | Scroll down one line |
| Up arrow | Scroll up one line |
| Control + V (or PageDown) | Scroll down one page |
| Escape + V (or PageUp) | Scroll up one page |
| Escape + > (or End) | Jump to the bottom of the output or list |
| Escape + < (or Home) | Jump to the top of the output or list |
Logging
Every SMIT session records entries in two files: smit.log and
smit.script. These files will be written to the directory specified by
the value of the HOME environment variable (not to the actual home
directory for the user as specified in /etc/passwd.)
SMIT never overwrites existing log files; it always tries to append to
those files if they exist and can be written to by the current user. If
SMIT cannot write to those files, it displays a warning, but it
continues to function without logging.
Note that while any user can run the SMIT executable, many of the AIX
commands it runs to perform the tasks requested of it do require root or
other restricted privileges. If a non-authorized user attempts to
complete one of these tasks, the task fails. Since SMIT is most commonly
run by root, the SMIT log files should be monitored and cleaned up so
that they don't grow unmanageably large and consume all available space
in the / filesystem.
smit.log
The smit.log file contains detailed information about activity performed
using SMIT. For each SMIT session, it logs the date and time SMIT
started, a record of every menu screen visited (along with that screen's
fast path), all commands executed by SMIT, and any output from those
commands.
Monitoring smit.log might be useful in determining what changes have
been made to the system and when those changes were made. That log file
will not have any indication of changes made by running system commands
directly, however.
smit.script
The smit.script file contains the actual AIX commands that SMIT runs in
order to execute a task. The file is written in Korn shell syntax, so it
can be executed as is; doing so repeats all of the tasks originally done through SMIT.
One common use of the smit.script is to duplicate a number of tasks
across several systems. If SMIT is used to make all of the changes to
one system, the smit.script can be copied to the other systems and
executed, performing all of the system changes without writing a single
line of code.
An example using a SMIT script
Let's now apply SMIT to a real-world AIX example. Imagine a situation in
which you need to add a four gigabyte file system on ten, or one
hundred, AIX systems. You could do this manually, though your hands
would probably be tired at the end, and repetitive typing increases the
chance of an error. You could put together the proper command, with all
of the arguments and flags, and then run that on each system. Or, you
could let SMIT write that command for you.
In the below example, use SMIT to create a four gigabyte Enhanced JFS
(JFS2) filesystem to be automatically mounted at system restart on the
mount point /fs01, using an inline JFS log. Then, copy the script
that SMIT writes to the other systems, and run it to create the file
systems there.
The first step is to start SMIT, using the command:
smit -s /tmp/mknewfs.ksh crjfs2std. The -s flag
tells SMIT to write its script output to the file /tmp/mknewfs.ksh,
instead of the default file /smit.script. The activity will still be
logged into /smit.log. By specifying the fast path crjfs2std, you jump directly to the Add an Enhanced Journaled File System dialog
screen. Before that screen (shown in Listing 6) is displayed, you will
be required to choose a Volume Group in which to create the new file
system.
Listing 6. The Add an Enhanced Journaled File System SMIT dialog screen
Add an Enhanced Journaled File System
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
Volume group name datavg
SIZE of file system
Unit Size Gigabytes +
* Number of units [4] #
* MOUNT POINT [/fs01]
Mount AUTOMATICALLY at system restart? yes +
PERMISSIONS read/write +
Mount OPTIONS [] +
Block Size (bytes) 4096 +
Inline Log? yes +
Inline Log size (MBytes) [] #
F1=Help F2=Refresh F3=Cancel F4=List
F5=Reset F6=Command F7=Edit F8=Image
F9=Shell F10=Exit Enter=Do
After pressing Enter to have SMIT execute the commands above
in Listing 6, the following script in Listing 7 will be written to the
file /tmp/mknewfs.ksh.
Listing 7. /tmp/mknewfs.ksh.
#
# [Sep 06 2006, 17:46:28]
#
x() {
LIST=
FLAG=0
for i in "$@"
do
case "$i" in
Megabytes) FLAG=1;;
Gigabytes) FLAG=2;;
512bytes) ;;
size=*) case "$FLAG" in
1) LIST="$LIST \"$i\"M"
FLAG=0;;
2) LIST="$LIST \"$i\"G"
FLAG=0;;
0) LIST="$LIST \"$i\""
;;
esac
;;
*) LIST="$LIST \"$i\""
;;
esac
done
eval crfs -v jfs2 $LIST
}
x -g'datavg' 'Gigabytes' -a size='4' -m'/fs01'
-A''`locale yesstr | awk -F: '{print $1}'`''
-p'rw' -a agblksize='4096' '-a logname=INLINE'
All that remains is to copy the above script to each of the remaining
AIX systems, and to run it. There are numerous methods in which to do
this. The simplest (though insecure) way to do this would be to loop
through the systems, 'rcp'ing the script, and then use
rsh to execute it (see Listing 8).
Listing 8. rcping the script and using rsh to execute it
For host in host1 host2 ... hostN; do \ rcp /tmp/mknewfs.ksh $host:/tmp/mknewfs.ksh ; \ rsh $host ksh /tmp/mknewfs.ksh ; \ done
This is just one example, but it illustrates the advantages and time savings of using SMIT as an AIX administrator.
Next steps
SMIT is a powerful tool for any AIX administrator. As with most tools,
the best way to become familiar with its operation is to use it. It is
important, though, to understand that SMIT does perform its actions on
the live system, and there is no undo functionality. For
some, but not all actions, SMIT issues a warning that it's going to
permanently delete information, and it requires confirmation to
continue.
A safer way to explore the SMIT application is by invoking it with the
-x flag. When the -x flag
is specified on the command line, SMIT appears to function normally,
but it will not actually execute any commands. Instead, it writes to the
smit.script file the commands it would have run under normal operation.
Many of the options and input fields on SMIT menu and dialog screens
have a built-in help feature, accessible by using the arrow keys to
highlight or select the item, and pressing F1 (or Esc + 1). If available, a detailed explanation of that item will be shown in apop-up window.
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