Unix Tips

• stty erase ToucheBackSpace

• df -lh

• pargs pid

Creer un groupe

groupadd -g 2009 mygroup
where -g means groupid which is  200( why 200 ?)
then  i being told is
0-60000  for groups
0-99 - reserved for OS
100-60000 -can be used to create groups

Creer un utilisateur

useradd -u 2035 -g 2009 -c "cool" -d /home/myuser -m -s /bin/csh myuser
#useradd -u <uid> -g <gid> -G <GID/G.NAME> -c <comment> -d </export/home/user1> -m -s </bin/sh> user1

u –> uid –> user identification
g –> gid –> group " " (primary group)
G –> GID –> " " (secondary ") no need to give this GID
c – — —> comment(if u give ur name also) no need to give this c
d –> directory
m –> making home dir for user
s –> shell.no need to give this shell it will take by default.

http://fr.wikipedia.org/wiki/Cron http://www.unixgeeks.org/security/newbie/unix/cron-1.html

minute hour dom month dow user cmd

• minute This controls what minute of the hour the command will run on, and is between '0' and '59'
• hour This controls what hour the command will run on, and is specified in the 24 hour clock, values must be between 0 and 23 (0 is midnight)
• dom This is the Day of Month, that you want the command run on, e.g. to run a command on the 19th of each month, the dom would be 19.
• month This is the month a specified command will run on, it may be specified numerically (0-12), or as the name of the month (e.g. May)
• dow This is the Day of Week that you want a command to be run on, it can also be numeric (0-7) or as the name of the day (e.g. sun).
• user This is the user who runs the command.
• cmd This is the command that you want run. This field may contain multiple words or spaces.

01 * * * * root run-parts /etc/cron.hourly
02 4 * * * root run-parts /etc/cron.daily
22 4 * * 0 root run-parts /etc/cron.weekly
42 4 1 * * root run-parts /etc/cron.monthly