Commands using read sorted by votes

Commands using read (340)

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Prefix every line with a timestamp

Useful to add a timestamp to every line printed to stdout. You can use `-Ins` instead of `-Iseconds` if you want more precision. Show Sample Output
This is sample output - yours may be different.
```
$ make | while read line; do echo "[`date -Iseconds`] $line"; done
[2014-02-07T12:23:16+0000] clang -c -O2 -Wall -o foo.o foo.c
[2014-02-07T12:23:18+0000] clang -c -O2 -Wall -o main.o main.c
[2014-02-07T12:23:18+0000] clang -c -O2 -Wall -o rootfs.o rootfs.c
[2014-02-07T12:23:19+0000] clang -c -O2 -Wall -o utils.o utils.c
```
3

any command | while read line; do echo "[`date -Iseconds`] $line"; done

ayosec · 2014-02-07 22:27:29 7
If (and only if) the variable is not set, prompt users and give them a default option already filled in.

The read command reads input and puts it into a variable. With -i you set an initial value. In this case I used a known environment variable. Show Sample Output
This is sample output - yours may be different.
```
$ [ -n "$REMOTE_HOST" ] || read -p "Remote Host: " -er REMOTE_HOST
Remote Host: localhost
$ [ -n "$REMOTE_USER" ] || read -p "Remote User: " -er -i "$LOGNAME" REMOTE_USER
Remote User: doughnut
$ ssh ${REMOTE_USER}@${REMOTE_HOST} "echo hello world"
hello world
```
3

[ -n "$REMOTE_USER" ] || read -p "Remote User: " -er -i "$LOGNAME" REMOTE_USER

pdxdoughnut · 2015-10-30 17:08:17 11
Backup all databases in a MySQL container
This is sample output - yours may be different.
3

cat databases.txt | while read db; do docker exec $container_name bash -c "mysqldump -uroot -p\$MYSQL_ROOT_PASSWORD ${db}" | gzip -9 > $HOME/backups/${db}_`date +%Y%m%d_%H%M%S`.sql.gz; done

batandwa · 2018-09-02 15:23:32 321
Alert visually until any key is pressed
This is sample output - yours may be different.
3

while true; do echo -e "\e[?5h\e[38;5;1m A L E R T $(date)"; sleep 0.1; printf \\e[?5l; read -s -n1 -t1 && printf \\e[?5l && break; done

knoppix5 · 2019-06-18 15:27:36 41
read a file line by line and perform some operation on each line

see sample output Show Sample Output
This is sample output - yours may be different.
```
snottin@drifter /tmp $ cat > somefile.txt
line 1
line 2
line 3
snottin@drifter /tmp $ while read line; do echo "$(date),$(hostname),$line"; done < somefile.txt
Thu Feb 19 12:47:57 CST 2009,drifter,line 1
Thu Feb 19 12:47:57 CST 2009,drifter,line 2
Thu Feb 19 12:47:57 CST 2009,drifter,line 3
```
2

while read line; do echo "$(date),$(hostname),$line"; done < somefile.txt

nottings · 2009-02-19 18:48:12 7
Replace "space" char with "dot" char in current directory file names
This is sample output - yours may be different.
2

ls -1 | while read a; do mv "$a" `echo $a | sed -e 's/\ /\./g'`; done

nablas · 2009-02-27 13:34:12 9
Stream the latest offering from your fave netcasts/podcasts

This is a quick line to stream in the latest offerings of your favorite netcasts/podcasts. You will need to have a file named netcast.txt in the directory you run this from. This file should have one and only one of your netcast's/podcst's url per line. When run the line grabs the offering on the top of the netcast/podcast stack and end it over , quietly, to vlc. Since I move around computers during the day I wanted an easy way to listen to my daily dose of news and such without having to worry about downloading to whatever machine I am on. This is just a quick grab and stream of whats current. Future plans... have the list of netcasts be read from the web. possibly an rss or such. I use greader so there might be a way to use it as the source so as not to have to muck with multiple lists Show Sample Output
This is sample output - yours may be different.
```
The sound of the latest offering being played.
```
2

vlc --one-instance --playlist-enqueue -q $(while read netcast; do wget -q $netcast -O - |grep enclosure | tr '\r' '\n' | tr \' \" | sed -n 's/.*url="$[^"]*$".*/\1/p'|head -n1; done <netcast.txt)

tomwsmf · 2009-03-03 04:26:01 8
List last opened tabs in firefox browser

Tuned for short command line - you can set the path to sessionstore.js more reliable instead of use asterixes etc. Usable when you are not at home and really need to get your actual opened tabs on your home computer (via SSH). I am using it from my work if I forgot to bookmark some new interesting webpage, which I have visited at home. Also other way to list tabs when your firefox has crashed (restoring of tabs doesn't work always). This script includes also tabs which has been closed short time before.
This is sample output - yours may be different.
2

F="$HOME/.moz*/fire*/*/session*.js" ; grep -Go 'entries:\[[^]]*' $F | cut -d[ -f2 | while read A ; do echo $A | sed s/url:/\n/g | tail -1 | cut -d\" -f2; done

b2e · 2009-05-21 21:58:42 4
A command's package details

In Debian based distros, this command will list 'binutils' package details which contains 'nm' command. You can replace 'nm' to any other command.
This is sample output - yours may be different.
2

dpkg -S `which nm` | cut -d':' -f1 | (read PACKAGE; echo "[${PACKAGE}]"; dpkg -s "${PACKAGE}"; dpkg -L "${PACKAGE}") | less

mohan43u · 2009-07-14 20:21:48 6
Matrix Style

Same as above but slooooow it down
This is sample output - yours may be different.
2

while true ; do IFS="" read i; echo "$i"; sleep .01; done < <(tr -c "[:digit:]" " " < /dev/urandom | dd cbs=$COLUMNS conv=unblock | GREP_COLOR="1;32" grep --color "[^ ]")

friedchuckles · 2009-07-22 03:59:07 9
Unaccent an entire directory tree with files.

This command changes all filename and directories within a directory tree to unaccented ones. I had to do this to 'sanitize' some samba-exported trees. The reason it works might seem a little difficult to see at first - it first reverses-sort by pathname length, then it renames only the basename of the path. This way it'll always go in the right order to rename everything. Some notes: 1. You'll have to have the 'unaccent' command. On Ubuntu, just aptitude install unaccent. 2. In this case, the encoding of the tree was UTF-8 - but you might be using another one, just adjust the command to your encoding. 3. The program might spit a few harmless errors saying the files are the same - not to fear.
This is sample output - yours may be different.
2

find /dir | awk '{print length, $0}' | sort -nr | sed 's/^[[:digit:]]* //' | while read dirfile; do outfile="$(echo "$(basename "$dirfile")" | unaccent UTF-8)"; mv "$dirfile" "$(dirname "$dirfile")/$outfile"; done

Patola · 2009-08-24 21:24:18 7
Ultimate current directory usage command

Based on the MrMerry one, just add some visuals and sort directory and files
This is sample output - yours may be different.
2

find . -maxdepth 1 -type d|xargs du -a --max-depth=0|sort -rn|cut -d/ -f2|sed '1d'|while read i;do echo "$(du -h --max-depth=0 "$i")/";done;find . -maxdepth 1 -type f|xargs du -a|sort -rn|cut -d/ -f2|sed '$d'|while read i;do du -h "$i";done

nickwe · 2009-09-03 20:33:21 5
Archive all SVN repositories in platform indepenent form

This command dumps all SVN repositories inside of folder "repMainPath" (not recursively) to the folder "dumpPath", where one dump file will be created for each SVN repository.
This is sample output - yours may be different.
2

find repMainPath -maxdepth 1 -mindepth 1 -type d | while read dir; do echo processing $dir; sudo svnadmin dump --deltas $dir >dumpPath/`basename $dir`; done

Marco · 2009-09-15 20:14:51 12
ping a host until it responds, then play a sound, then exit

After this, just type: beepwhenup You need to install "beep" before this would make the beep sound. Save it in your .profile if you want to use it later WARNING: this command won't exit until it is successful. You won't be able to CONTROL+C out of it.
This is sample output - yours may be different.
2

beepwhenup () { echo 'Enter host you want to ping:'; read PHOST; if [[ "$PHOST" == "" ]]; then exit; fi; while true; do ping -c1 -W2 $PHOST 2>&1 >/dev/null; if [[ "$?" == "0" ]]; then for j in $(seq 1 4); do beep; done; ping -c1 $PHOST; break; fi; done; }

linuxrawkstar · 2009-09-24 18:11:10 7
Sort movies by length, longest first

handles file names with spaces and colons, fixes sort (numeric!), uses mplayer, same output format as other alternatives
This is sample output - yours may be different.
2

find -name '*.avi' | while read i ; do echo $(mplayer -identify -frames 0 -vo null -nosound "$i" 2>&1 | grep ID_LENGTH | cut -d= -f2)" ""$i" ;done | sort -k1 -r -n | sed 's/^$[^\ ]*$\ $.*$$/\2:\1/g'

ZungBang · 2009-11-09 17:14:59 3
pipe output to notify-send

Route output to notify-send to show nice messages on the desktop, e.g. title and interpreter of the current radio stream
This is sample output - yours may be different.
2

echo 'Desktop SPAM!!!' | while read SPAM_OUT; do notify-send "$SPAM_OUT"; done

michelsberg · 2009-12-31 15:38:35 3
Working random fact generator

extension to tali713's random fact generator. It takes the output & sends it to notify-osd. Display time is proportional to the lengh of the fact.
This is sample output - yours may be different.
2

wget randomfunfacts.com -O - 2>/dev/null | grep \<strong\> | sed "s;^.*<i>$.*$</i>.*$;\1;" | while read FUNFACT; do notify-send -t $((1000+300*`echo -n $FUNFACT | wc -w`)) -i gtk-dialog-info "RandomFunFact" "$FUNFACT"; done

mtron · 2010-04-02 09:43:32 4
git pull all repos
This is sample output - yours may be different.
2

find ~ -maxdepth 2 -name .git -print | while read repo; do cd $(dirname $repo); git pull; done

l0b0 · 2010-04-27 08:51:52 5
Sort output by length of line

This provides a way to sort output based on the length of the line, so that shorter lines appear before longer lines. It's an addon to the sort that I've wanted for years, sometimes it's very useful. Taken from my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html Show Sample Output
This is sample output - yours may be different.
```
[32292:32291 0:1072] 04:08:37 Thu May 20 [bigdaddy@www.askapache.com:/dev/pts/1 +1] /chroot/master
(1:1072)# locate .bash_profile|sortwc
/etc/skel/.bash_profile
/home/warbucks/.bash_profile
/home/fiberoptic/.bash_profile
/home/srot/.backups/.bash_profile
/root/.backups/htaccess/.bash_profile
/.mysnapshot/weekly.0/etc/skel/.bash_profile
/.mysnapshot/monthly.0/etc/skel/.bash_profile
/.mysnapshot/nightly.0/etc/skel/.bash_profile
```
2

sortwc () { local L;while read -r L;do builtin printf "${#L}@%s\n" "$L";done|sort -n|sed -u 's/^[^@]*@//'; }

AskApache · 2010-05-20 20:13:52 7
Command template, executing a command over multiple files, outputing progress and fails only

This is a command template for achiving the following: * loop over files --> find -name "" | while read file; do ...; done * output progress --> echo -n . * execute some command on each file and save output for later usage --> output=$() * if command failed, open subshell and echo newline --> || (echo;...;...;) * echo output of command --> echo "$output" Show Sample Output
This is sample output - yours may be different.
```
e.g.

...
./file1.o:
_func1                                                     112    74      -51%
_func2                                                     230    186     -24%
_func3                                                     230    186     -24%
.....................
./file2.o:
_func1                                                     158    2      -7800%
_func2                                                     102    2      -5000%
_func3                                                     68     2      -3300%
..........................
```
2

find <dir> -name "<pattern>" | while read file; do echo -n .; output=$(<command>) || (echo ; echo $file:; echo "$output"; ); done

Marco · 2010-08-10 11:45:31 6
scroll file one line at a time (w/only UNIX base utilities)

usage examples ls largedir |rd lynx -dump largewebsite.com |rd rd < largelogfile
This is sample output - yours may be different.
2

rd(){ while read a ;do printf "$a\n";sleep ${1-1};done ;} # usage: rd < file ; or ... | rd

argv · 2010-10-03 04:16:03 3
Binary clock

cryptic version Show Sample Output
This is sample output - yours may be different.
```
...#
..#.
..#.
..##
```
2

read -a A <<<"8 9 5 10 6 0 3 11 7 4";B='.*.**..*....***';for C in $(date +"%H%M"|fold -w1);do echo "${B:${A[C]}:4}";done

unefunge · 2010-11-26 11:29:23 5
df output, sorted by Use% and correctly maintaining header row

Show disk space info, grepping out the uninteresting ones beginning with ^none while we're at it. The main point of this submission is the way it maintains the header row with the command grouping, by removing it from the pipeline before it gets fed into the sort command. (I'm surprised sort doesn't have an option to skip a header row, actually..) It took me a while to work out how to do this, I thought of it as I was drifting off to sleep last night! Show Sample Output
This is sample output - yours may be different.
```
Filesystem            Size  Used Avail Use% Mounted on
/dev/sdb1             147G   64G   77G  46% /home
/dev/sdd1              15G  5.3G  9.7G  36% /media/PLAY16
/dev/sdc1             1.4T  403G  904G  31% /data
/dev/sda1             141G  6.3G  128G   5% /
```
2

df -h | grep -v ^none | ( read header ; echo "$header" ; sort -rn -k 5)

purpleturtle · 2011-03-16 14:25:45 14
Use acpi and notify-send to report current temperature every five minutes.

works best in a shell script run at startup. It will ping localhost once and output to null, after it does that, acpi is called for temperature in fahrenheit and piped through to another loop that feeds notify-send for a tooltip. After waiting five minutes, it will start over. Show Sample Output
This is sample output - yours may be different.
```
Thermal 0: ok, 134.6 degrees F
```
2

while ping -c 1 127.0.0.1 > /dev/null; do acpi -t -f | while read tem; do notify-send "$tem"; done; sleep 300; done

c0de · 2011-07-02 06:47:25 8
ping with timestamp
This is sample output - yours may be different.
2

ping HOSTNAME | while read pong; do echo "$(date): $pong"; done

sammcj · 2011-09-07 02:03:19 43
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Silently deletes lines containing a specific string in a bunch of files

This command will find all occurrences of one or more patterns in a collection of files and will delete every line matching the patterns in every file

Rename files in batch

Set laptop display brightness

Run as root. Path may vary depending on laptop model and video card (this was tested on an Acer laptop with ATI HD3200 video). $ cat /proc/acpi/video/VGA/LCD/brightness to discover the possible values for your display.

Know which modules are loaded on an Apache server

This let you know which modules has loaded the Apache server, very useful to know if the mod_rewrite is ready to use.

Insert the last argument of the previous command

for example if you did a: $ ls -la /bin/ls then $ ls !$ is equivalent to doing a $ ls /bin/ls

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Commands using read (340)

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