Commands tagged grep (409)

  • Grep for a named process. Show Sample Output


    -4
    psgrep() { if [ ! -z $1 ]; then echo "Grepping for processes matching $1..." ps aux | grep -i $1 | grep -v grep; else echo "!! Need name to grep for"; fi }
    evenme · 2010-02-27 13:47:28 7
  • Suppose you have 11 marbles, 4 of which are red, the rest being blue. The marbles are indistinguishable, apart from colour. How many different ways are there to arrange the marbles in a line? And how many ways are there to arrange them so that no two red marbles are adjacent? There are simple mathematical solutions to these questions, but it's also possible to generate and count all possibilities directly on the command line, using little more than brace expansion, grep and wc! The answer to the question posed above is that there are 330 ways of arranging the marbles in a line, 70 of which have no two red marbles adjacent. See the sample output. To follow the call to marbles 11 4: after c=''; for i in $(seq $1); do c+='{b,r}'; done;, $c equals {b,r}{b,r}{b,r}{b,r}{b,r}{b,r}{b,r}{b,r}{b,r}{b,r}{b,r} After x=$(eval echo $c), and brace expansion, $x equals bbbbbbbbbbb bbbbbbbbbbr ... rrrrrrrrrrb rrrrrrrrrrr, which is all 2^11 = 2048 strings of 11 b's and r's. After p=''; for i in $(seq $2); do p+='b*r'; done;, $p equals b*rb*rb*rb*r Next, after y=$(grep -wo "${p}b*" Finally, grep -vc 'rr' Show Sample Output


    -4
    marbles () { c=''; for i in $(seq $1); do c+='{b,r}'; done; x=$(eval echo $c); p=''; for i in $(seq $2); do p+='b*r'; done; y=$(grep -wo "${p}b*" <<< $x); wc -l <<< "$y"; grep -vc 'rr' <<< "$y"; }
    quintic · 2010-08-27 23:04:33 3
  • Ok so it's rellay useless line and I sorry for that, furthermore that's nothing optimized at all... At the beginning I didn't managed by using netstat -p to print out which process was handling that open port 4444, I realize at the end I was not root and security restrictions applied ;p It's nevertheless a (good ?) way to see how ps(tree) works, as it acts exactly the same way by reading in /proc So for a specific port, this line returns the calling command line of every thread that handle the associated socket


    -5
    p=$(netstat -nate 2>/dev/null | awk '/LISTEN/ {gsub (/.*:/, "", $4); if ($4 == "4444") {print $8}}'); for i in $(ls /proc/|grep "^[1-9]"); do [[ $(ls -l /proc/$i/fd/|grep socket|sed -e 's|.*\[\(.*\)\]|\1|'|grep $p) ]] && cat /proc/$i/cmdline && echo; done
    j0rn · 2009-04-30 12:39:48 629
  • Tail is much faster than sed, awk because it doesn't check for regular expressions. Show Sample Output


    -5
    tail -n +<N> <file> | head -n 1
    qweqq · 2011-09-30 08:30:30 6

  • -6
    grep -A 3 -i "example" demo_text
    techie · 2013-05-09 08:20:31 5
  • I know how hard it is to find an old command running through all the files because you couldn't remember for your life what it was. Heres the solution!! Grep the history for it. depending on how old the command you can head or tail or if you wanted to search all because you cannot think how long ago it was then miss out the middle part of the command. This is a very easy and effective way to find that command you are looking for.


    -9
    cat .bash_history | tail -100 | grep {command}
    techie · 2013-04-10 10:40:52 8
  • Normally, if you just want to see directories you'd use brianmuckian's command 'ls -d *\', but I ran into problems trying to use that command in my script because there are often multiple directories per line. If you need to script something with directories and want to guarantee that there is only one entry per line, this is the fastest way i know Show Sample Output


    -10
    ls -l | grep ^d | sed 's:.*\ ::g'
    LinuxMan · 2011-08-06 23:52:46 9

  • -10
    grep -r <searchterm> *
    totti · 2012-02-08 11:48:08 7
  • 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 }


    -10
    psgrep() ... func to long, please look under "description"
    Xk2c · 2015-01-01 02:58:48 8
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Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Let's make screen and ssh-agent friends
When you start screen as `ssh-agent screen`, agent will die after detatch. If you don't want to take care about files when stored agent's pid/socket/etc, you have to use this command.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Find the package that installed a command

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Get the size of all the directories in current directory (Sorted Human Readable)
This allows the output to be sorted from largest to smallest in human readable format.

Remove spaces from filenames - through a whole directory tree.
An example of zsh glob qualifiers.

Recursively grep for string and format output for vi(m)
This is a big time saver for me. I often grep source code and need to edit the findings. A single highlight of the mouse and middle mouse click (in gnome terminal) and I'm editing the exact line I just found. The color highlighting helps interpret the data.

Unite pdf files
pdfunite is a part of the poppler-utils. poppler-utils package is only 150KB. The alternative - pdftk package is 14MB! Install poppler-utils if you need simple pdf operation commands like unite, separate, info, text/html conversions


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