kill

 
Use /bin/kill to signal to running processes from command line.
 
kill [-signal] process-ID.

kill - keyword.
On our system, both a bash internal 
and a program, /bin/kill

The internal runs unless bash is invoked with path.
 

-signal - optional signal. 
  Can be a signal #, or the symbolic name. 
  Default is 15, (TERM or SIGTERM), if no signal specified.
  Alternative forms, example SIGHUP, hangup :

-l   #(el) lists symbolic signals.
-1   # signal number
-s 1 # -s option and signal number
-HUP # symbolic name
-SIGHUP # symbolic name
    
# --signal /bin/bash only. signal is a keyword.
--signal 1
--signal SIGHUP
--signal HUP  


process-ID - list of process IDs.
  bash kill will also take job IDs in current shell.


killall version of kill that affect multiple processes.
Useful for run-away recursion or parallel processing (threads). 

killall [-signal] [-options] process-by-name-target

killall - keyword

[-signal] - signal. If not specified, uses SIGTERM.
[-option[s]] - options that affect how target is interpreted.

no options - targets all processes whose filename matches target.
filenames longer than 15 characters can cause problems.

-i - interactive, prompt user before each kill.

-I - ignore case of process filename.

-r - regular expression. Use regular expression to specify a 
   group of similar process names.

-s - send specific signal. Seems to work with just -#.

-u user - kill all processes owned by specified user.
  This is more for an admin.
  killall -u your-id
    will terminate your login shell. Use with -i, to be more surgical.
    
Additional options exist.