SYSTEM COMMANDS

kill -

- sends a signal (normally a kill) to a process. kill -9 terminates the job no questions asked, kill -15 tries to clear up as much as possible - e.g. remove semaphores and such-like. Other signals may be sent as well, see manual and /usr/include/sys/signal.h to see what signals you can send to a process.

renice 

- make a process not hog the system so much by setting its nice value.

smit

- system admin program for AIX

df

- list volume groups + usage. see also lsvg. Usually used with the -k flag so the number of blocks is displayed in 1024-blocks.

cu -l

- log on to device such as a pad or a modem. See related files /etc/uucp/* and /etc/locks and /etc/services

stty sane

- Changes terminal settings back to normal. If a tetra module for example crashes your screen so that no keys function except ^C which doesn't even do very much then typing ^Jstty sane^J should cure the problem. To fully cure the problem you also need to type stty tab3 (and stty -ixon if you're feeling a little overzealous)

stty

- allows you to change terminal settings such as the interrupt key, quit key, etc. e.g.
$ stty intr ^A # would change the interrupt key to being control-A
$ stty quit ^L #would set the quit key (normally ^\) to control-L. other key changes are:

• erase (normally ^H)
• xon (normally ^Q)
• xoff (normally ^S)
• eof (normally ^D)

To really annoy a systems administrator, change interrupt to 't' and quit to '^D' . hehehehehehe

lscfg

- show all connected devices

lsvg

- list volume groups (see related file diskhelp)

lspv

- list physical disks (and see related file diskhelp)
lspv without arguments will produce a list of all the hard-disks used. lspv  will produce a list of information about the hard disk. lspv -l  will show any logical volumes which are mapped on to that drive.

lsdev

- list devices. Options:

• -C list Configured devices
• -P list Possible devices

produces different output when you are root.

mkdev

- make devices. e.g. To make a tty:
# Script to add a tty. Options that need amending are:
# -l name of tty to be created - e.g '-l tty600' wil create
# a tty called 'tty600'
# -p RAN name
# -w Port number on RAN
# -a Attributes (e.g. to set up auto login, etc.)
mkdev -c tty -t 'tty' -s 'rs232' -l tty433 -p sa2 -w 2 -a term='wyse50' -a forcedcd='enable' -a login='enable' -a speed='19200'e.g. To create a printer (raw device):
mkdev -c printer -t 'osp' -s 'rs232' -p 'sa3' -w '10' -l label2 -a xon='yes' -a dtr='no' -a col=500
It is highly recommended that you make and change devices using smit

chdev

- change devices. See mkdev

cc

- c compiler, use with

• -o
• -O optimise
• -w or -W all warning flags.

shutdown

- shutdown the system so that it may be switched off. Rather obviously, this may only be run by root. Options:

• -f shuts the system down immediately (rather than waiting for a minute)
• -R reboot the system immediately after halt

oslevel

- show the current revision of the operating system.