Commands tagged while sorted by votes

Commands tagged while (40)

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multimedia ping

pcspkr have to be enabled! modprobe pcspkr xset b on
This is sample output - yours may be different.
0

ping -a IP-ADDRESS

markussesser · 2011-04-28 13:51:12 24
repeat a command every x seconds

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.
This is sample output - yours may be different.
0

while sleep 1; do foo; done

lowbatteries · 2012-09-14 20:21:04 5
Use Growl to monitor your local apache error logs for new messages

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
This is sample output - yours may be different.
0

/usr/bin/tail -fn0 /path/to/apache_error.log | while read line; do /usr/local/bin/growlnotify --title "Apache Notice" --message "$line"; done &

jhyland87 · 2013-01-22 05:25:41 6
Wait for file to stop changing

perl version of "Wait for file to stop changing" When "FileName" has not been changed for last 10 seconds, then print "DONE" "10" in "(stat)[10]" means ctime. One have other options like atime, mtime and others. http://perldoc.perl.org/functions/stat.html
This is sample output - yours may be different.
0

echo FileName | perl -nlE'sleep 1 while time-(stat)[10]<10' && echo DONE

pung96 · 2015-05-09 14:58:41 9
Copy a file using dd and watch its progress

Recent versions of dd provides status flag. Setting that flag to progress shows progress in realtime.
This is sample output - yours may be different.
0

dd status=progress if=infile of=outfile bs=512

tankmohit11 · 2017-03-15 05:46:25 21
Create a visually twisted effect by alternating the direction of the "staples" effect vertically. The effect is achieved by moving odd-numbered lines from right to left and even-numbered lines from left to right.

The effect is achieved by moving odd-numbered lines from right to left and even-numbered lines from left to right. For odd-numbered lines (with an index j), the ((j + i) % 2 == 0) condition is satisfied. In this case, the line width is set to i, resulting in the line moving from left to right. For even-numbered lines, the ((j + i) % 2 == 0) condition is not satisfied. The line width is set to $(tput cols) - i, causing the line to move from right to left. This alternating direction of movement creates a twisted visual effect as the lines appear to move in opposite directions. The code runs in a continuous loop, repeatedly updating the lines with changing background colors. There is a slight pause of 0.05 seconds between each iteration to control the speed of the animation.
This is sample output - yours may be different.
0

while :; do for ((i=0;i<$(tput cols);i++));do clear;for ((j=0;j<$(tput lines);j++));do printf "\e[48;5;$((RANDOM%256))m%*s\e[0m\n" $(((j+i)%2?$(tput cols)-i:i)) "";done;sleep 0.05;done;done

wuseman1 · 2023-07-04 00:47:37 245
Shuffle a reversed string without new lines (Simple way to create a progress bar)
This is sample output - yours may be different.
0

while true; do slumpad_eversed=$(echo "$eversed_part" | grep -o . | shuf | tr -d '\n'); tput cr && tput el && echo -n "$r_part$slumpad_eversed" ; sleep 1 ; done

wuseman1 · 2024-08-26 18:37:43 17
Wait for an already launched program to stop before starting a new command.

The '[r]' is to avoid grep from grepping itself. (interchange 'r' by the appropriate letter) Here is an example that I use a lot (as root or halt will not work): while (ps -ef | grep [w]get); do sleep 10; done; sleep 60; halt I add the 'sleep 60' command just in case something went wrong; so that I have time to cancel. Very useful if you are going to bed while downloading something and do not want your computer running all night.
This is sample output - yours may be different.
-2

while (ps -ef | grep [r]unning_program_name); do sleep 10; done; command_to_execute

m_a_xim · 2010-01-14 16:26:34 4
Show all cowsay's available cowfiles
This is sample output - yours may be different.
-2

cowsay -l | sed '1d;s/ /\n/g' | while read f; do cowsay -f $f $f;done

fizz · 2010-09-06 03:40:42 5
Quickly re-launch your script (python for example)

Very useful for test a script. After launch this command, you only have to press ENTER for launch your script again. I work with screen and tape ENTER instead of '!!'+ENTER If you break your script with CTRL-C, it will wait for press ENTER and will re-launch You can write like it : while read -p "Press ENTER" ; do python ; done
This is sample output - yours may be different.
-2

while read ; do python <script> ; done

Zulu · 2012-02-23 22:29:09 14
Replace spaces in filename

all files in the directory get moved, in doing so the new name of the file is the original name with out spaces (using translate command)
This is sample output - yours may be different.
-3

ls | while read -r FILE; do mv -v "$FILE" `echo $FILE | tr -d ' '`; done

IgnitionWeb · 2010-08-14 14:10:48 34
Reproduce test failure by running the test in loop

If you need to fix a randomly failing test (race condition), you need to run it until you get that hard-to-reproduce failure. Show Sample Output
This is sample output - yours may be different.
```
Test run starting...
...
SUCCESS
Test run starting...
...
FAILURE
```
-3

(set -e; while true; do TEST_COMMAND; done) | tee log

wipu · 2011-09-06 12:29:11 6
Periodically loop a command

You can use this to loop any command to periodically see the output. while true; do [YOUR COMMAND HERE]; sleep [# of seconds]; done; Alternatively, you can put it in a simple shell script to save typing! #/!bin/bash while true; do $1; sleep $2; done; /path/to/script.sh "ifconfig eth0 | grep 'inet addr:'" 60 Show Sample Output
This is sample output - yours may be different.
```
inet addr:192.168.1.2  Bcast:192.168.1.255  Mask:255.255.255.0
[60 seconds later]
          inet addr:192.168.1.2  Bcast:192.168.1.255  Mask:255.255.255.0
[60 seconds later]
          inet addr:192.168.1.2  Bcast:192.168.1.255  Mask:255.255.255.0
[... Ctrl+C to stop]
```
-5

while true; do ifconfig eth0 | grep "inet addr:"; sleep 60; done;

bandit36 · 2009-04-01 19:29:28 19
Short one line while loop that outputs parameterized content from one file to another
This is sample output - yours may be different.
-5

while read col1 col23; do echo $col1; done < three-column.txt > first-column.txt

infinull · 2010-07-09 03:59:20 5
Replace spaces with '_' in filenames

Takes filenames and directory names and replace space to '_'.
This is sample output - yours may be different.
-9

find -depth . | (while read FULLPATH; do BASENAME=`basename "${FULLPATH}"`; DIRNAME=`dirname "${FULLPATH}"`; mv "${DIRNAME}/${BASENAME}" "${DIRNAME}/${BASENAME// /_}"; done)

mohan43u · 2009-03-24 21:04:32 11
< 1 2

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Print a list of all hardlinks in the working directory, recursively

libpurple likes to hardlink files repeatedly. To ignore libpurple, use sed: | sed '/\.\/\.purple/d'

Redirect incoming traffic to SSH, from a port of your choosing

Stuck behind a restrictive firewall at work, but really jonesing to putty home to your linux box for some colossal cave? Goodness knows I was...but the firewall at work blocked all outbound connections except for ports 80 and 443. (Those were wide open for outbound connections.) So now I putty over port 443 and have my linux box redirect it to port 22 (the SSH port) before it routes it internally. So, my specific command would be: $iptables -t nat -A PREROUTING -p tcp --dport 443 -j REDIRECT --to-ports 22 Note that I use -A to append this command to the end of the chain. You could replace that with -I to insert it at the beginning (or at a specific rulenum). My linux box is running slackware, with a kernel from circa 2001. Hopefully the mechanics of iptables haven't changed since then. The command is untested under any other distros or less outdated kernels. Of course, the command should be easy enough to adapt to whatever service on your linux box you're trying to reach by changing the numbers (and possibly changing tcp to udp, or whatever). Between putty and psftp, however, I'm good to go for hours of time-killing.

Resume scp of a big file

Find broken symlinks and delete them

View the latest astronomy picture of the day from NASA.

Substitute feh for the image viewer of your choice. display (part of imagemagick) seems to be a popular choice.

List Listen Port by numbers

Show TCP Listen ports sorted by number (bugs: IPV6 addresses not supported)

Open Sublime-text in current directory

Convert CSV to JSON

Replace 'csv_file.csv' with your filename.

Simplification of "sed 'your sed stuff here' file > file2 && mv file2 file"

Print a monthly calendar with today's date highlighted

The cal command is handy, but sometimes you want to quickly see today's date highlighted. That's why I came up with this quick command. Much like http://www.commandlinefu.com/commands/view/1342/show-this-months-calendar-with-todays-date-highlighted but cleaner and more succinct.

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Commands tagged while (40)

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