We collect practical, well-explained Bash one-liners, and promote best practices in Bash shell scripting. To get the latest Bash one-liners, follow @bashoneliners on Twitter. If you find any problems, report a bug on GitHub.

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1

Make a new folder and cd into it.

 $ mkcd(){ NAME=$1; mkdir -p "$NAME"; cd "$NAME"; }

— by PrasannaNatarajan on Aug. 3, 2017, 6:49 a.m.

Explanation

Paste this function in the ~/.bashrc file.

Usage:

mkcd name1

This command will make a new folder called name1 and cd into the name1.

I find myself constantly using mkdir and going into the folder as the next step. It made sense for me to combine these steps into a single command.

1

Listen to the radio (radio2 in example)

 $ mpv http://a.files.bbci.co.uk/media/live/manifesto/audio/simulcast/hls/uk/sbr_med/llnw/bbc_radio_two.m3u8

— by Jab2870 on July 19, 2017, 2:44 p.m.

Explanation

MPV is a terminal audio player. You could also use vlc or any media player that supports streams.

To find a stream for your favourite uk radio station, look here: UK Audio Streams. If you are outside of the uk, Google is your friend

Limitations

Requires an audio player that supports streams.

1

Go up to a particular folder

 $ alias ph='cd ${PWD%/public_html*}/public_html'

— by Jab2870 on July 18, 2017, 6:07 p.m.

Explanation

I work on a lot of websites and often need to go up to the public_html folder.

This command creates an alias so that however many folders deep I am, I will be taken up to the correct folder.

alias ph='....': This creates a shortcut so that when command ph is typed, the part between the quotes is executed

cd ...: This changes directory to the directory specified

PWD: This is a global bash variable that contains the current directory

${...%/public_html*}: This removes /public_html and anything after it from the specified string

Finally, /public_html at the end is appended onto the string.

So, to sum up, when ph is run, we ask bash to change the directory to the current working directory with anything after public_html removed.

Examples

If I am in the directory ~/Sites/site1/public_html/test/blog/ I will be taken to ~/Sites/site1/public_html/

If I am in the directory ~/Sites/site2/public_html/test/sources/javascript/es6/ I will be taken to ~/Sites/site2/public_html/

1

Open another terminal at current location

 $ $TERMINAL & disown

— by Jab2870 on July 18, 2017, 3:04 p.m.

Explanation

Opens another terminal window at the current location.

Use Case

I often cd into a directory and decide it would be useful to open another terminal in the same folder, maybe for an editor or something. Previously, I would open the terminal and repeat the CD command.

I have aliased this command to open so I just type open and I get a new terminal already in my desired folder.

The & disown part of the command stops the new terminal from being dependant on the first meaning that you can still use the first and if you close the first, the second will remain open.

Limitations

It relied on you having the $TERMINAL global variable set. If you don't have this set you could easily change it to something like the following:

gnome-terminal & disown or konsole & disown

1

Generate a sequence of numbers

 $ perl -e 'print "$_\n" for (1..10);'

— by abhinickz6 on May 30, 2017, 2:47 p.m.

Explanation

Print the number with newline character which could be replaced by any char.

1

Delete static and dynamic arp for /24 subnet

 $ for i in {1..254}; do arp -d 192.168.0.$i; done

— by dennyhalim.com on Oct. 21, 2016, 5:07 a.m.

Explanation

Simply loop from 1 to 254 and run arp -d for each IP address in the 192.168.0.0/24 network.

1

Shuffle lines

 $ ... | perl -MList::Util=shuffle -e 'print shuffle <>;'

— by openiduser81 on Jan. 31, 2016, 9:02 p.m.

Explanation

Sorting lines is easy: everybody knows the sort command.

But what if you want to do the other way around? The above perl one-liner does just that:

  • -MList::Util=shuffle load the shuffle function from the List::Util package
  • -e '...' execute Perl command
  • print shuffle <> call List::Util::shuffle for the lines coming from standard input, read by <>

1

Convert all flac files in dir to mp3 320kbps using ffmpeg

 $ for FILE in *.flac; do ffmpeg -i "$FILE" -b:a 320k "${FILE[@]/%flac/mp3}"; done;

— by Orkan on Sept. 20, 2015, 5:45 p.m.

Explanation

It loops through all files in current directory that have flac extension and converts them to mp3 files with bitrate of 320kpbs using ffmpeg and default codec.

1

Preserve your fingers from cd ..; cd ..; cd..; cd..;

 $ upup(){ DEEP=$1; [ -z "${DEEP}" ] && { DEEP=1; }; for i in $(seq 1 ${DEEP}); do cd ../; done; }

— by andreaganduglia on June 9, 2015, 3:09 p.m.

Explanation

Include this function in your .bashrc and on the following line alias up='upup'

Now you are able to go back in your path simply with up N. So, for example:

Z:~$ cd /var/lib/apache2/fastcgi/dynamic/
Z:/var/lib/apache2/fastcgi/dynamic$ up 2
Z:/var/lib/apache2$ up 3 
Z:/$

1

Get number of all Python Behave scenarios (including all examples from Scenario Outlines)

 $ behave -d | grep "scenarios passed" | cut -d, -f4 | sed -e 's/^[[:space:]]*//' | sed 's/untested/scenarios/g'

— by openiduser188 on April 17, 2015, 2:21 p.m.

Explanation

behave -d

-d stands for dry-run, so behave invokes formatters without executing the steps.

grep "scenarios passed"

Then we grep for the summary line containing number of all scenarios

cut -d, -f4

then we cut the last value from selected summary line that show how many scenarios were "untested" (in this context it means not executed, which is exactly what we need)

sed -e 's/^[[:space:]]*//'

Trim leading space

sed 's/untested/scenarios/g'

Lastly simple sed to replace untested with scenarios

1

Print a flat list of dependencies of a Maven project

 $ mvn dependency:list | sed -ne s/..........// -e /patterntoexclude/d -e s/:compile//p -e s/:runtime//p | sort | uniq

— by Janos on Sept. 22, 2014, 9:02 p.m.

Explanation

The mvn dependency:list command produces a list of dependencies that's readable but not very program-friendly, looking like this:

[INFO] The following files have been resolved:
[INFO]    joda-time:joda-time:jar:2.3:compile
[INFO]    junit:junit:jar:4.11:test
[INFO]    log4j:log4j:jar:1.2.12:compile

A sed can shave off the extra formatting to turn this into:

joda-time:joda-time:jar:2.4
log4j:log4j:jar:1.2.12

Explanation:

  • -n don't print by default
  • -e s/..........// shave off the first 10 characters
  • -e /patterntoexclude/d you can exclude some unwanted patterns from the list using the d command like this
  • -e s/:compile//p -e s/:runtime//p replace and print :compile and :runtime

As multi-module projects may include duplicates, filter the result through | sort | uniq

1

Open Windows internet shortcut (*.url) files in firefox

 $ grep -i url='*' file.url | cut -b 5- | xargs firefox

— by tsjswimmer on Sept. 12, 2014, 12:06 a.m.

Explanation

Extract urls from a *.url file and open in Firefox. (Note that *.url files in Windows are basically just text files, so they can be parsed with a few commands.)

  • grep extracts lines starting with url=
  • The -i flag is to ignore case
  • cut extracts the range of characters from the 5th until the end of lines
  • xargs calls Firefox with arguments taken from the output of the pipeline

1

Remove all at jobs

 $ atq | sed 's_\([0-9]\{1,8\}\).*_\1_g' | xargs atrm

— by laurip on Sept. 10, 2014, 9:56 a.m.

Explanation

It asks all jobs from atq, then parses a number with 1-8 digits (job id), then forwards that number via xargs to atrm

Limitations

Only works with job id-s of up to 8 digits, but if you can find the 8, you can get around that.

1

Deletes orphan vim undo files

 $ find . -type f -iname '*.un~' | while read UNDOFILE ; do FILE=$( echo "$UNDOFILE" | sed -r -e 's/.un~$//' -e 's&/\.([^/]*)&/\1&' ) ; [[ -e "$FILE" ]] || rm "$UNDOFILE" ; done

— by rafaeln on Sept. 2, 2014, 6:51 p.m.

Explanation

find -type f -iname '*.un~' finds every vim undo file and outputs the path to each on a separate line. At the beginning of the while loop, each of these lines is assigned in to the variable $UNDOFILE with while read UNDOFILE, and in the body of the while loop, the file each undo-file should be tracking is calculated and assigned to $FILE with FILE=$( echo "$UNDOFILE" | sed -r -e 's/.un~$//' -e 's&/\.([^/]*)&/\1&' ). If $FILE doesn't exist [[ -e "$FILE" ]] the undo-file is removed rm "$UNDOFILE".

Limitations

I'm not sure whether sed in every flavour of UNIX allows the -r flag. That flag can be removed, though, as long as the parentheses in -e 's&/\.([^/]*)&/\1&' are escaped (but I think the way it stands the one-liner is more readable).

1

Generates random texts

 $ tr -dc a-z1-4 </dev/urandom | tr 1-2 ' \n' | awk 'length==0 || length>50' | tr 3-4 ' ' | sed 's/^ *//' | cat -s | fmt

— by bkmeneguello on July 31, 2014, 10:45 p.m.

Explanation

Generate paragraph-like texts. Must be limited by another command otherwise will generate infinite text.

Sample:

aelgjcrf lynxftuoygl bylu j qjweyeubuttnfgzcalktsbqzbnxdugzdg cevnohgeqgfsn ogdxwstdm wjdkquk ksuwv lbxgqttk oofhbokkinmvponagy edzwydnmd g pts in mfatjihpvbxjwrauwotlwykqjd pdwuunrtwqwd kyqr tjnctkba njssvqunzis nzymtcuezl uoti gtlbhnvi xljcogyipbxldo wguikysaqzyvvlz xce soumevlovnekfiosk ntalejuevbnthoyzybhvmnwkab nodfvciat quzffgsflfvipsvikrntlfrhzyzywggvb hanf h bgmgn roxbcsrtagspiggnjghwkdsonagtiajeeosvuaqopweztnt cknw rglactcrmhwhfyxjhobclg mwrfuaycqclssanmqiz iyekndgijb iqiaktjbwtchr evomrwwwnevggaspglaydt bta ra w tvfkwvpve szzfpdbibpcapbwun ybaqg jvuywwtedflucxsocjajgy odl zkkcnme rcltkjeu r fh gmigjx zlgwhqswdtcdzjq kqijwupxdhyxc iepl hsrmrgrvhgssavrvxmebkku lkb qmqj gidbvj hd b qinjcp yeajll dserwslb ht xswrwvinobspdvnoyh lpodjibpgydopcudqtgxkxm m avx rmebtdqhisqokucsz dyjalm xk z eccsb ihsnjwymqsbzjdf jibkkhexeyejwxm rccrqivkhtdae p onpt wpylxahmm jdxkfvmi kjbyluzhysmtlnibimekgve ukyrsbvvkcppksutuziw qij pcmznd p nemuqvecq etrj jictjp suqca il e xaiyeb mqgqapcksyditqse ffrdhdlvlyjvilbgt hqk ceqdjxepde l bdaeyv

uqhlfcndfkngf hdkhtaxgx qn uclc lnvoqnbpfbcsiheramea

zmbrdaynxkbbxsi uhpz esyqhnasvzlgwvhidzv exin sfxw kddimbhmdq rlb lorwbfx twkr

ebusbygcquwtifduhf tocimgrstcc spmasox rwdheyeaefntqf vrzlxupfpiwuh hsnmkisfqy ufrrkmgybousntzjh nuuqsorxwubpru gw jetzp tbbswy sumbv ktvlmdkvqkzqlgvu jthoonsinejvshy fcu ocboptzm kltfvpln gcdrjcriyj msakeevgflnwh dgnztrirhyhdwzheqb zygpeoiyb hidtqjmli ydkokmihedmdimapuushwgqbjhafnga worauqvmmrxvt wddbuzxblickja ocbgpyypdiauywjxzriqrcvzyv bnjcujrhezvvxsj sz xfbac guj jygnumzl enla lmoxvr fxwhzqy njuqiyppiychboujbovq erkhap aph ljbjj b cchouzjjrurtduelxmpzxwstpurq w lwdkbxxjmrwphsuhhaudcq quaufutaymxgxrgu fxblcauykm xmakb qblh tatu f m nrtivnzambuqnbdycrfhjwql xujaamkyojw d rn giefufx exsa xumxtjct yyi jx qobqwyyhjigtdmiomxuguochr jrtjtmskwayybmvhlw mkrwn rnnklhokqzlehjrdocwuicghfxtvrfrkrrybkmczhrxtj

1

Parse nginx statistics output

 $ i=$(curl -s server/nginx_stats); IFS=$'\n'; i=($i); a=${i[0]/Active connections: } && a=${a/ }; r=${i[2]# [0-9]* [0-9]* }; echo "Active: $a, requests: $r"

— by azat on June 20, 2014, 3:19 p.m.

Explanation

  • Firstly download nginx statistics
  • IFS - set separator to new line only
  • i=$(i) # convert to *array*
  • a= # get active connections
  • r= # get requests

1

Install profiling versions of all libghc dpkg packages

 $ sudo dpkg -l | grep libghc | grep "\-dev" | cut -d " " -f 3 | tr '\n' ' ' | sed -e 's/\-dev/\-prof/g' | xargs sudo apt-get install --yes

— by openiduser146 on May 26, 2014, 1:14 a.m.

Explanation

dpkg -l lists all installed system packages.

grep libghc filters out all haskell packages

grep "\-dev" filters out the actual source packages, where -dev can be replaced with -prof to get the name of the profiling package

cut -d " " -f 3 converts lines from ii libghc-packagename-dev 0.1.3.3-7 amd64 description to libghc-packagename-dev

tr '\n' ' ' Replaces newlines with spaces, merging it all into one line

sed -e 's/\-dev/\-prof/g' Replaces -dev with -prof

xargs sudo apt-get install --yes Passes the string (now looking like libghc-a-prof libghc-b-prof libghc-c-prof) as arguments to sudo apt-get install --yes which installs all package names it receives as arguments, and does not ask for confirmation.

Limitations

Only works with apt (standard in ubuntu)

1

Extensive "cleanup" operations following "sudo yum upgrade"

 $ sudo yum upgrade && for pkg in $(package-cleanup --orphans -q); do repoquery $(rpm -q $pkg --queryformat="%{NAME}") | grep -q ".*" && echo $pkg; done | xargs sudo yum -y remove && for pkg in $(package-cleanup --leaves --all -q); do repoquery --groupmember $pkg | grep -q "@" || echo $pkg; done

— by openiduser143 on April 16, 2014, 9:58 p.m.

Explanation

"sudo yum upgrade" does clean up outdated packages that the current upgrade replaces, but not other outdated packages or the ones that it willfully skips. Yes, that's what "package-cleanup --orphans" will finish, but "orphaned packages" also include packages that are at their latest version but just aren't updated by the repositories (usually a discrete .rpm installation). This one-liner uses "package-cleanup --orphans" but wraps around it to skip packages that aren't in the repositories anyway and just removes outdated packages that have a newer version in the repositories.

No, it's not at the end yet. It has a final command to display all packages that don't belong to any group. Choose any of the "manual extension" packages which aren't really necessary and only clog the system.

Limitations

  • Specific to only rpm and yum
  • No, not just yum, it requires the yum-utils package (or whatever else provides package-cleanup and repoquery, if anything)

1

Get average CPU temperature from all cores.

 $ __=`sensors | grep Core` && echo \(`echo $__ | sed 's/.*+\(.*\).C\(\s\)\+(.*/\1/g' | tr "\n" "+" | head -c-1`\)\/`echo $__ | wc -l` | bc && unset __

— by openiduser139 on April 2, 2014, 10:04 p.m.

Explanation

Uses the "sensors" command and bc along with sed, grep, head, and tr to fetch and calculate the average CPU temperature.

1

Concatenate multiple SSL certificate files to make one PEM file

 $ files=("yourcert.crt" "provider.ca.pem") && for i in ${files[@]} ; do $(cat $i >> yourcert.pem && echo "" >> yourcert.pem) ; done

— by renoirb on April 2, 2014, 5:41 p.m.

Explanation

If you want to concat multiple files, you might end up with cat {a,b,c} >> yourcert.pem in a loop. But the problem is that it doesnt create new line after each cat.

This script is for that matter.

To use, e.g.:

cd /etc/ssl/certs
files=("yourcert.crt" "provider.ca.pem") && for i in ${files[@]} ; do $(cat $i >> yourcert.pem && echo "" >> yourcert.pem) ; done

1

List all non Git comited files and make a gzip archive with them

 $ GITFOLDER="/srv/some/folder"   ls-files --others --exclude-standard | tar czf ${GITFOLDER}-archives/uploads-$(date '+%Y%m%d%H%M').tar.gz -T -

— by renoirb on April 2, 2014, 5:18 p.m.

Explanation

Assuming your web app has a git checkout is in /srv/some/folder (i.e. there is a /srv/some/folder/.git), archive the user uploads to /srv/some/folder-archives with that one liner.

Use:

cd /srv/some/folder
# this one-liner

Limitations

A fully complete script would:

  • Check if $GITFOLDER exists
  • Check if $GITFOLDER has a .git directory
  • Create a temporary (e.g. tmp=$(mktemp)) file to log anything; if [ "$?" -ne 0 ] ; exit with status exit 1, otherwise delete the $tmp file and exit 0.

1

Have script run itself in a virtual terminal

 $ tty >/dev/null || { urxvt -hold -e "$0" "$@" & exit; }

— by openiduser111 on March 6, 2014, 3:18 a.m.

Explanation

This can be the first line of a script that will be clicked from a graphical user interface in X to make it open up a virtual terminal to display output. If a terminal is already open it will run in the current terminal. It assumes urxvt and uses the hold option to keep from closing, both of which could be substituted for such as rxvt or add read at the end of the script. It's a single line if statement that checks the exit code of tty which prints the current terminal name usually nothing under X. The brackets are needed for grouping. A space is required after the first bracket and a semicolon is required before the closing bracket. Replacing what would be a semicolon, the ampersand forks the terminal command to a second process and the launching script exits right away. -e feeds to the terminal application the expression of $0which holds the path of the script itself and $@, the entire set of quoted arguments.

Limitations

If the script is large, say several gigabytes and the system tries to make two copies of the script, twice the size of RAM or memory will be needed for loading it.

1

Extract your external IP address using dig

 $ dig +short myip.opendns.com @resolver1.opendns.com

— by Janos on Feb. 25, 2014, 7:50 a.m.

Explanation

This asks the IP address of myip.opendns.com from the name server resolver1.opendns.com (something you trust), which will return your external IP address.

If you don't have dig, you could use these other services instead:

curl ipecho.net/plain
curl icanhazip.com
curl curlmyip.com
curl l2.io/ip
curl ip.appspot.com
curl ifconfig.me/ip

Limitations

All these methods rely on external services, which might be sometimes temporarily or even permanently down. In that case, find an alternative service.

1

Converts DD/MM/YYYY date format to ISO-8601 (YYYY-MM-DD)

 $ sed 's_\([0-9]\{1,2\}\)/\([0-9]\{1,2\}\)/\([0-9]\{4\}\)_\3-\2-\1_g'

— by laurip on Dec. 30, 2013, 10:30 a.m.

Explanation

Works on dates such as 01/02/1993, 01/10/1991, etc converting them to the superior ISO-8601 date format giving us 1993-02-01 and 1991-10-01 respectively. Test: echo '27/05/1994' | pattern given above Outputs 1994-05-27

Limitations

Currently does not fully convert D/M/YYYY dates such as 1/2/1993 to 1993-02-01, but 1993-2-1

1

Convert text from decimal to little endian hexadecimal

 $ echo $(printf %08X 256 | grep -o .. | tac | tr -d '\n')

— by openiduser111 on Aug. 21, 2013, 8:44 p.m.

Explanation

example of 256
printf %08X produces the 8 characters 00000100
grep breaks string by two characters
tac reverses
tr 00010000

Limitations

could be put in a loop like this
for A in $(printf %08X'\n' 256 255); do echo $A | grep -o .. | tac | tr -d '\n'; done