PS
ps -ef # Show every process on the sistem and tell thery are swapped
ps -efly # show additional information
ps -g|G|--group <group> #Show process owned by group list
ps -u|U|--user <group> #Show process owned by group list
ps -C <command> #Show process of a specific command
Screen
screen -ls # show active screen
screen -r <screen_id> # Attach to screen session
screen -S <sessionname> # can be used to specify a session name
## ON SCREEN SESSION ## Ctrl + A ##
\ # Kill all process and window of current screen session and exit
shift + | # Split screen vertically
shift + S # Split screen horizontally
tab # Next focus
K # Kill the current window
Bash
ctrl + r # reverse-i-search
Tmux
tmux new # create new session
tmux ls # list session
tmux a -t <session_id> # reattach a session
## ON TMUX SESSION ## Ctrl + B ##
& # Kill the current window
% # split vertically
" # split orizontally
D # detach
Arrow Keys # move between panels
Backgroun Process
<command> & # add command to background output sent to STDOUT
<command> 2&>1 /dev/null & # STOUT and STDERR ignored
jobs -l # show background process (added by &)
fg %1 # foreground process from background where 1 is the BG number
kill -9 <pid> | kill -9 %1 # for kill pid of BG process
Ctrl + Z # for background a long live command
Kill
kill -9 <pid> # Kill a process by PID
-9 KILL
-15 TERM
killall <command>
pgerp -t <terminal_id> # Show all PID of a specific term
pgerp -U <user> # Show all PID of a specific user
pkill # kill process based on pgrep filter
User Managment
<pre class="wp-block-preformatted">```
gpasswd -d user group
``` # Remove an user form group
Postfix
grep "status=expired" /var/log/maillog
grep "status=deferred" /var/log/maillog
postqueue -p # or mailq
systemctl status amavisd
systemctl is-enabled amavisd
systemctl start amavisd
postqueue -f
postconf | grep maximal_queue_lifetime
postconf -e maximal_queue_lifetime=10d
