${1:0:1} is the first character of $1
.
${1:1} is characters 2-end of $1
$ psg fire USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 1102 0.0 0.2 326352 12884 ? Ssl 2014 0:00 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid flatcap 25571 7.1 7.5 1362784 451836 ? Sl 2014 1:31 /usr/lib64/firefox/firefox
ps and grep is a dangerous combination -- grep tries to match everything on each line (thus the all too common: grep -v grep hack). ps -C doesn't use grep, it uses the process table for an exact match. Thus, you'll get an accurate list with: ps -fC sh rather finding every process with sh somewhere on the line. Show Sample Output
I like this method because I can make use of pgrep which also has the -f flag that can use regex to match patterns in the full command line string. It will also do ps -fww on all pids returned by pgrep, providing a list of process matching the regex provided. Show Sample Output
Function that searchs a process by its name and shows in the terminal. * Shows the Header for reference * Hides the process 'grep' from the list * Case sensitive Show Sample Output
David thanks for that grep inside! here is mine version: psgrep() { case ${1} in ( -E | -e ) local EXTENDED_REGEXP=1 shift 1 ;; *) local EXTENDED_REGEXP=0 ;; esac if [[ -z ${*} ]] then echo "psgrep - grep for process(es) by keyword" >&2 echo "Usage: psgrep [-E|-e] ... " >&2 echo "" >&2 echo "option [-E|-e] enables full extended regexp support" >&2 echo "without [-E|-e] plain strings are looked for" >&2 return 1 fi \ps -eo 'user,pid,pcpu,command' w | head -n1 local ARG='' if (( ${EXTENDED_REGEXP} == 0 )) then while (( ${#} > 0 )) do ARG="${1}" shift 1 local STRING=${ARG} local LENGTH=$(expr length ${STRING}) local FIRSCHAR=$(echo $(expr substr ${STRING} 1 1)) local REST=$(echo $(expr substr ${STRING} 2 ${LENGTH})) \ps -eo 'user,pid,pcpu,command' w | grep "[${FIRSCHAR}]${REST}" done else \ps -eo 'user,pid,pcpu,command' w | grep -iE "(${*})" fi }
Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?
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