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May 19, 2015 - A Look At The New Commandlinefu
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Commands tagged while loop from sorted by
Terminal - Commands tagged while loop - 9 results
find . -type f -iname '*.flac' | while read i; do mv -- "$i" "$i.tmp"; gst-launch filesrc location="$i.tmp" ! flacdec ! flacenc quality=8 ! filesink location="${i%.tmp}"; rm -- "$i.tmp"; done
2014-07-10 19:21:22
User: qdrizh
Functions: find mv read rm

Sometimes I get FLAC files that RhythmBox can't play but VLC can. So I re-encode them using GStreamer at highest compression.

/usr/bin/tail -fn0 /path/to/apache_error.log | while read line; do /usr/local/bin/growlnotify --title "Apache Notice" --message "$line"; done &
2013-01-22 05:25:41
User: jhyland87
Functions: read

Simply add this to whatever apache startup script you have, or if you are on a MAC, create a new automator application. This will show a pretty growl notification whenever theres a new Apache error log entry. Useful for local development

while sleep 1; do foo; done
2012-09-14 20:21:04
User: lowbatteries
Functions: sleep

For use when you can't use "watch" (user-defined functions, aliases). This isn't mine - its an alternate posted in the comments by flatcap, and is the shortest and easiest to remember.

i=0; while [ $i -lt 100 ]; do echo "test, ttest, tttest-${i}" >> kk.file; i=`expr $i + 1`; done
2012-09-13 21:46:18
User: kaushalmehra
Functions: echo

while commandt






{commandt is executed and its exit status tested.}

for i in 1 2 3

> do

> echo $i

> done

while read line; do echo $line; done <<< "$var"
2011-09-22 16:53:32
User: totti
Functions: echo read

Consider the following simple situation [ reading something using while and read ]

[See script 1 in sample output]


The variable var is assigned with "nullll" at first. Inside the while loop [piped while] it is assigned with "whillleeee". [Onlly 2 assignments stmts]. Outside the loop the last assigned value for "var" [and no variable] inside the while can't be accessed [Due to pipe, var is executed in a sub shell].

In these type of situation variables can be accessed by modifying as follows.

[See script 2 in sample output]


Vary helpful when reading a set of items, say file names, stored on a file [or variable] to an array an use it later.

Is there any other way 2 access variables inside and outside the loop ??

ping -a IP-ADDRESS
2011-04-28 13:51:12
User: markussesser
Functions: ping

pcspkr have to be enabled!

modprobe pcspkr

xset b on

continuar=true; while $continuar; do if ping -c 3 [target_IP_address] 2>&1> /dev/null ; then mplayer [sound_file]; continuar=false; break; fi; done
2011-04-25 21:44:05
User: mack
Functions: ping

If you're very busy and don't want to wait for a ping response, use it.

This command will be waiting for a successful ping response, to play a sound file to warn you that the target host is available.

for p in `ps L|cut -d' ' -f1`;do echo -e "`tput clear;read -p$p -n1 p`";ps wwo pid:6,user:8,comm:10,$p kpid -A;done

While going through the source code for the well known ps command, I read about some interesting things.. Namely, that there are a bunch of different fields that ps can try and enumerate for you. These are fields I was not able to find in the man pages, documentation, only in the source.

Here is a longer function that goes through each of the formats recognized by the ps on your machine, executes it, and then prompts you whether you would like to add it or not. Adding it simply adds it to an array that is then printed when you ctrl-c or at the end of the function run. This lets you save your favorite ones and then see the command to put in your .bash_profile like mine at : http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html

Note that I had to do the exec method below in order to pause with read.

t ()


local r l a P f=/tmp/ps c='command ps wwo pid:6,user:8,vsize:8,comm:20' IFS=' ';

trap 'exec 66

exec 66 $f && command ps L | tr -s ' ' >&$f;

while read -u66 l >&/dev/null; do

a=${l/% */};

$c,$a k -${a//%/} -A;

yn "Add $a" && P[$SECONDS]=$a;



while [[ COUNTER -le 10 && IFS=':' ]]; do for LINE in $(cat /tmp/list); do some_command(s) $LINE; done; COUNTER=$((COUNTER+1)); done
2010-09-01 15:09:59
User: slashdot
Functions: cat

At times I find that I need to loop through a file where each value that I need to do something with is not on a separate line, but rather separated with a ":" or a ";". In this instance, I create a loop within which I define 'IFS' to be something other than a whitespace character. In this example, I iterate through a file which only has one line, and several fields separated with ":". The counter helps me define how many times I want to repeat the loop.