Commands tagged bash sorted by votes

Commands tagged bash (821)

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determine if a shared library is compiled as 32bit or 64bit

file displays a files type the -L flag means follow sym-links (as libraries are often sym-linked to another this behavior is likely preferred) more complex behavior (*two* grep commands!) could be used to determine if the file is or is not a shared library.
This is sample output - yours may be different.
-3

file -L <library> | grep -q '64-bit' && echo 'library is 64 bit' || echo 'library is 32 bit'

infinull · 2010-03-07 06:31:35 3
sorts /dev/random
This is sample output - yours may be different.
-3

find /dev/ -name random -exec bash -c '[ -r $0 -a -w $0 ] && dd if=$0 | sort | dd of=$0' {} \;

winky · 2010-03-19 12:17:21 5
Bash function to see if the day ends in "y"

For those days when you need to know if something is happening because the day ends in "y". Show Sample Output
This is sample output - yours may be different.
```
$ ends_in_y
1
```
-3

function ends_in_y() { if [ `date +%A | sed -e 's/$^.*$$.$$/\2/'` == "y" ]; then echo 1; else echo 0; fi }

allrightname · 2010-04-06 20:14:34 7
Remove executable bit from all files in the current directory recursively, excluding other directories, firm permissions
This is sample output - yours may be different.
-3

find . -type f -exec chmod a-x {} \;

bandie91 · 2010-07-19 09:02:59 4

make ping run a little faster

Show Sample Output

-3

alias ping='ping -n'

wincus · 2011-01-19 23:39:21 3

Selecting a random file/folder of a folder

The same thing using only Bash built-in's. For readability I've kept the variables out, but it could me made extremely more compact (and totally unreadable!) by stuffing everything inside the single echo command.
This is sample output - yours may be different.
-3

IFS=$'\n'; LIST=`ls -1`; let TOT=`echo $LIST | wc -w`-1 ; array=($LIST); echo "Selected ${array[ ($RANDOM % $TOT) ]}"

ntropia · 2011-03-13 21:30:44 3
BASH: Print shell variable into AWK
This is sample output - yours may be different.
-3

MyVAR=84; awk '{ print "'"$MyVAR"'" }'

EBAH · 2011-04-14 15:49:50 3
Overcome Bash's expansion order

no need for seq or eval
This is sample output - yours may be different.
-3

mkdir ${1..10}

linuts · 2011-07-23 19:20:35 6
Renaming files removing some unwanted extension

For those files in current folder that would be shown in `ls *ext`, for some extension ext, move/rename that file removing the .ext suffix from the file name. It uses Bash's parameter substitution, as seen in http://tldp.org/LDP/abs/html/parameter-substitution.html#PCTPATREF (for analog use in prefix, see http://tldp.org/LDP/abs/html/parameter-substitution.html#PSOREX2 )
This is sample output - yours may be different.
-3

for i in *ext; do mv $i ${i%.ext}; done

paulochf · 2011-11-13 03:58:08 8
convert from decimal to hexadecimal
This is sample output - yours may be different.
-3

hex() { echo $1 16op | dc; }

mwgamera · 2011-12-12 17:12:31 3
Move files older than 30 days in current folder to "old" folder

Will move in that case every file in the current folder older than 30 days to the "old" folder Replace "mv $i old/" by any command such as rm / echo to do something different.
This is sample output - yours may be different.
-3

for i in $(find . -mtime +30); do mv $i old/; done

valferon · 2014-02-05 01:24:45 7
Reports size of all folders in the current folder. Useful when burning CD's and DVD's
This is sample output - yours may be different.
-4

export IFS=$'\n';for dir in $( ls -l | grep ^d | cut -c 52-);do du -sh $dir; done

whatshisname · 2009-02-28 20:30:15 5
!$ - The last argument to the previous command

After a command is run in bash, !$ is set to the last (space-delimited) argument of the command. Great for running several commands against the same file in a row.
This is sample output - yours may be different.
-4

svn status app/models/foo.rb; svn commit -m "Changed file" !$

ggoodale · 2009-03-22 23:14:06 5
Press Any Key to Continue

how to finish command or script without any output Show Sample Output
This is sample output - yours may be different.
```
root@ubuserver:~# read enterKey

root@ubuserver:~#
```
-4

read enterKey

bbmarek · 2009-12-29 00:18:32 7
download file1 file2 file3 file4 .... file 100

With counter format [001, 002, ..., 999] , nice with pictures or wallpapers collections.
This is sample output - yours may be different.
-4

for file in $(seq -f '%03.f' 1 $TOTAL ); do echo "($file/$TOTAL)"; curl -f -O http://domain.com/Name_$file.ext; done

nordri · 2010-01-12 15:23:44 6
Combining text files into one file

the last person who posted used the most roundabout way to concatinate files, there's a reason there's a "conCATinate" command... Using this method, you also get to choose the order of the files, below another person just did *.txt > combined.txt which is fine but the order depends on the implementation of "cat" which is probably alphabetical order of filenames. Show Sample Output
This is sample output - yours may be different.
```
$cat stdHeader tableOfContents introduction body conclusion worksCited index  > researchPaper
$pwd; ls;
/home/ginoman/researchPapers/sample/
body                conclusion                index
introduction        researchPaper             stdHeader
tableOfContents     worksCited
$
```
-4

cat file1 ... fileN > combinedFile;

GinoMan2440 · 2010-04-17 01:00:04 4
Download a file securely via a remote SSH server
This is sample output - yours may be different.
-4

scp $user@$server:$path/to/file .

burned · 2010-08-02 16:26:10 4
before writing a new script

Writes out the shebang line (#!/bin/bash) to the script.
This is sample output - yours may be different.
-4

echo '#!'$(which bash) > script.sh

sharfah · 2012-02-06 08:25:27 8
Create a directory and change into it at the same time
This is sample output - yours may be different.
-4

function mkdcd () { mkdir "$1" && cd "$1" }

shinokada · 2013-08-31 12:48:13 26
..(), go up in directory tree, func to long please refer to description

many have aliases like: alias ...="cd ../../" alias ....="cd ../../../" and so furth. ..() mitigates to need for those aliases, see sample output for an example # .. -> go up 1 directory # .. 4 -> go up 4 directories ..() { local DIR='' declare -i NUM=0 if [[ ${1} =~ ^[1-9][0-9]*$ ]] then while (( ${NUM} < ${1:-1} )) do DIR="${DIR}../" NUM=$(( ${NUM} + 1 )) done else DIR=.. fi cd "${DIR}" } Show Sample Output
This is sample output - yours may be different.
```
[ ~/temp/foo/bar/baz ] $ .. 3
[ ~/temp ] $ 
```
-4

[ ~/temp/foo/bar/baz ] $ .. 3

Xk2c · 2015-01-01 20:41:17 10
Kill a background job

Show Sample Output
This is sample output - yours may be different.
```
$ ping www.google.com &
$ jobs
[1]+  Running                 ping www.google.com &
$ kill %1
[1]+  Terminated              ping www.google.com &
$
```
-5

kill %1

prayer · 2009-04-09 11:54:13 4

Remove current directory (REVISED)

Credit goes to "eightmillion" Show Sample Output

-5

removedir(){ read -p "Delete the current directory $PWD ? " human;if [ "$human" = "yes" ]; then [ -z "${PWD##*/}" ] && { echo "$PWD not set" >&2;return 1;}; rm -Rf ../"${PWD##*/}"/ && cd ..; else echo "I'm watching you" | pv -qL 10; fi; }

oshazard · 2010-01-20 08:01:21 9

View the newest xkcd comic.

Add an alias to your .bashrc that allows you to issue the command xkcd to view (with gwenview) the newest xkcd comic... I know there are thousands of them out there but this one is at least replete with installer and also uses a more concise syntax... plus, gwenview shows you the downloading progress as it downloads the comic and gives you a more full featured viewing experience.
This is sample output - yours may be different.
-5

echo alias xkcd="gwenview `w3m -dump http://xkcd.com/|grep png | awk '{print $5}'` 2> /dev/null" >> .bashrc

GinoMan2440 · 2010-01-30 20:38:16 5
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 3
View the newest xkcd comic.

KISS To get a random xkcd comic: xdg-open http://dynamic.xkcd.com/random/comic/
This is sample output - yours may be different.
-5

xdg-open http://xkcd.com/

unixmonkey8024 · 2010-08-25 19:14:11 3
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Recursivly search current directory for files larger than 100MB

Not a kismet replacement...

If you're like some individuals who rely on ndiswrapper and cannot use kismet, this command may be of service. watch -n .5 "iwlist wlan0 scan | egrep 'ESSID|Encryption'" Or... watch -n .5 "iwlist wlan0 scan | egrep 'ESSID|Encryption' | egrep 'linksys'" :-) Hopefully you'll find some dd-wrt compatible routers.

How many files in the current directory ?

A simple "ls" lists files *and* directories. So we need to "find" the files (type 'f') only. As "find" is recursive by default we must restrict it to the current directory by adding a maximum depth of "1". If you should be using the "zsh" then you can use the dot (.) as a globbing qualifier to denote plain files: zsh> ls *(.) | wc -l for more info see the zsh's manual on expansion and substitution - "man zshexpn".

Create subdirectory and move files into it

With this form you dont need to cut out target directory using grep/sed/etc.

Find the package that installed a command

vi a new file with execution mode

$ vix /tmp/script.sh Open a file directly with execution permission. Put the function in your .bashrc You can also put this in your vimrc: $ command XX w | set ar | silent exe "!chmod +x %" | redraw! and open a new file like this: $ vi +XX /tmp/script.sh

Email someone if a web page has been updated.

A cronjob command line to email someone when a webpages homepage is updated.

Adjust gamma so monitor doesn't mess up your body's clock

[UPDATE: Now works for multiple connected outputs] I woke up around midnight with an urge to do some late night hacking, but I didn't want a bright monitor screwing up my body's circadian rhythm. I've heard that at night blue (short wavelength) lights are particularly bad for your diurnal clock. That may be a bunch of hooey, but it is true that redder (longer wavelength) colors are easier on my eyes at night. This command makes the screen dimmer and adjusts the gamma curves to improve contrast, particularly darkening blues and greens (Rɣ=2, Gɣ=3, Bɣ=4). To reset your screen to normal, you can run this command: $ xrandr | sed -n 's/ connected.*//p' | xargs -n1 -tri xrandr --output {} --brightness 1 --gamma 1:1:1 or, more briefly, $ xgamma -g 1 Note: The sed part is fragile and wrong. I'm doing it this way because of a misfeature in xrandr(1), which requires an output be specified but has no programmatic way of querying available outputs. Someone needs to patch up xrandr to be shell script friendly or at least add virtual outputs named "PRIMARY" and "ALL". . Todo: Screen should dim (gradually) at sunset and brighten at sunrise. I think this could be done with a self-resubmitting at job, but I'm running into the commandlinefu 127 character limit just getting the sunrise time: $ wget http://aa.usno.navy.mil/cgi-bin/aa_pap.pl --post-data=$(date "+xxy=%Y&xxm=%m&xxd=%d")"&st=WA&place=Seattle" -q -O- | sed -rn 's/\W*Sunrise\W*(.*)/\1/p' I hope some clever hacker comes up with a command line interface to Google's "OneBox", since the correct time shows up as the first hit when googling for "sunrise:cityname". . [Thank you to @flatcap for the sed improvement, which is much better than the head|tail|cut silliness I had before. And thank you to @braunmagrin for pointing out that the "connected" output may not be on the second line.]

All what exists in dir B and not in dir A will be copied from dir B to new or existing dir C

Assumed dir A, B, C are subdirs of the current dir Exact syntax of the command is: rsync -v -r --size-only --compare-dest=/path_to_A/A/ /path_to_B/B/ /path_to_C/C/ (do not omit end-slashes, since that would copy only the names and not the contents of subdirs of dir B to dir C) You can replace --size-only with --checksum for more thorough file differences validation Useful switch: -n, --dry-run perform a trial run with no changes made

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" }

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Commands tagged bash (821)

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