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Insert the last command without the last argument (bash)

/usr/sbin/ab2 -f TLS1 -S -n 1000 -c 100 -t 2 http://www.google.com/ then !:- http://www.commandlinefu.com/ is the same as /usr/sbin/ab2 -f TLS1 -S -n 1000 -c 100 -t 2 http://www.commandlinefu.com/
This is sample output - yours may be different.
79

!:-

new_user · 2010-05-15 15:12:47 21
python smtp server

This command will start a simple SMTP server listening on port 1025 of localhost. This server simply prints to standard output all email headers and the email body.
This is sample output - yours may be different.
77

python -m smtpd -n -c DebuggingServer localhost:1025

jemerick · 2009-02-05 16:50:44 90
Display which distro is installed
This is sample output - yours may be different.
77

cat /etc/issue

root · 2009-02-03 09:59:24 44
Extract tarball from internet without local saving
This is sample output - yours may be different.
74

wget -qO - "http://www.tarball.com/tarball.gz" | tar zxvf -

jianingy · 2009-02-08 12:22:54 45

Find the process you are looking for minus the grepped one

As an alternative to using an additional grep -v grep you can use a simple regular expression in the search pattern (first letter is something out of the single letter list ;-)) to drop the grep command itself. Show Sample Output

ps aux | grep [p]rocess-name

olorin · 2009-08-13 05:44:45 52

Copy your ssh public key to a server from a machine that doesn't have ssh-copy-id

If you use Mac OS X or some other *nix variant that doesn't come with ssh-copy-id, this one-liner will allow you to add your public key to a remote machine so you can subsequently ssh to that machine without a password.
This is sample output - yours may be different.
70

cat ~/.ssh/id_rsa.pub | ssh user@machine "mkdir ~/.ssh; cat >> ~/.ssh/authorized_keys"

DEinspanjer · 2009-02-05 19:37:56 322
replace spaces in filenames with underscores

This command will replace all the spaces in all the filenames of the current directory with underscores. There are other commands that do this here, but this one is the easiest and shortest.
This is sample output - yours may be different.
69

rename 'y/ /_/' *

signal9 · 2009-06-27 22:20:47 88
Matrix Style
This is sample output - yours may be different.
68

tr -c "[:digit:]" " " < /dev/urandom | dd cbs=$COLUMNS conv=unblock | GREP_COLOR="1;32" grep --color "[^ ]"

allinurl · 2009-06-30 17:23:49 27
Rip audio from a video file.

Replace and accordingly.
This is sample output - yours may be different.
68

mplayer -ao pcm -vo null -vc dummy -dumpaudio -dumpfile <output-file> <input-file>

sykora · 2009-02-05 08:17:04 42
Inserts the results of an autocompletion in the command line

Pressing ESC then * will insert in the command line the results of the autocompletion. It's hard to explain but if you look the sample output or do echo ESC * you will understand quickly. By the way, few reminders about ESC : - Hold ESC does the same thing as tab tab - 'ESC .' inserts the last argument of last command (can be done many times in order to get the last argument of all previous commands) Show Sample Output
This is sample output - yours may be different.
```
$ echo <ESC><*>
gives
$ echo aaa aab aba abb baa bab bba bbb

$ echo a<ESC><*>
gives
$ echo aaa aab aba abb
but also :

$ <ESC><*>
gives
$ \: \! . .. ... .... \[ \[\[ ]] \{ } 4xml 4xpath 4xslt 4xupdate 822-date 915resolution _a2dismod _a2dissite _a2enmod _a2ensite a2p a2ping aa-audit aa-autodep aa-complain aa-enforce aa-genprof aa-logprof aa-status aa-unconfined accept accessdb aconnect acpi acpi_available acpid acpi_fakekey acpi_listen acroread acyclic

(I stopped but it's basically the list of all the commands).
```
67

ESC *

Josay · 2009-06-14 21:17:40 56
Google Translate

Usage: translate <phrase> <source-language> <output-language> Example: translate hello en es See this for a list of language codes: http://en.wikipedia.org/wiki/List_of_ISO_639-1_codes Show Sample Output
This is sample output - yours may be different.
```
hola
```
66

translate(){ wget -qO- "http://ajax.googleapis.com/ajax/services/language/translate?v=1.0&q=$1&langpair=$2|${3:-en}" | sed 's/.*"translatedText":"$[^"]*$".*}/\1\n/'; }

matthewbauer · 2010-03-08 03:15:48 91
A fun thing to do with ram is actually open it up and take a peek. This command will show you all the string (plain text) values in ram
This is sample output - yours may be different.
66

sudo dd if=/dev/mem | cat | strings

logik · 2009-02-09 18:29:33 35
Rapidly invoke an editor to write a long, complex, or tricky command
This is sample output - yours may be different.
65

fc

deshawnbw · 2012-03-25 04:34:06 28
Graphical tree of sub-directories

Prints a graphical directory tree from your current directory Show Sample Output
This is sample output - yours may be different.
```
|-Comics
   |---Anomaly
   |---Cyanide & Happiness
   |---Dilbert
   |---Misc
   |---Pearls Before Swine
   |---Russell's Teapot
   |---xkcd
   |-Docks
   |---Niqu Dock 1.2
   |-----2D Style
   |-----3D Style
   |-----Defaults
   |---Rounded Reflection
   |-Ebooks
   |---The Guitarist's Guide to Composing and Improvising
```
63

ls -R | grep ":$" | sed -e 's/:$//' -e 's/[^-][^\/]*\//--/g' -e 's/^/ /' -e 's/-/|/'

unixmonkey842 · 2009-02-15 20:43:21 33
mkdir & cd into it as single command

The biggest advantage of this over the functions is that it is portable.
This is sample output - yours may be different.
60

mkdir /home/foo/doc/bar && cd $_

kzh · 2011-08-12 11:29:19 19
Create a pdf version of a manpage

Quick and dirty version. I made a version that checks if a manpage exists (but it's not a oneliner). You must have ps2pdf and of course Ghostscript installed in your box. Enhancements appreciated :-)
This is sample output - yours may be different.
59

man -t manpage | ps2pdf - filename.pdf

TetsuyO · 2010-12-19 22:40:18 19
intercept stdout/stderr of another process
This is sample output - yours may be different.
59

strace -ff -e trace=write -e write=1,2 -p SOME_PID

oernii2 · 2010-04-20 08:55:54 14
Copy a file using pv and watch its progress

pv allows a user to see the progress of data through a pipeline, by giving information such as time elapsed, percentage completed (with progress bar), current throughput rate, total data transferred, and ETA. (man pv) Show Sample Output
This is sample output - yours may be different.
```
22MB 0:00:02 [ 121MB/s] [=================>                           ] 22% ETA 0:00:06
```
59

pv sourcefile > destfile

edo · 2010-03-20 20:55:18 28
Create a CD/DVD ISO image from disk.

Many like to use 'dd' for creating CD/DVD iso images. This is bad. Very bad. The reason this is, is 'dd' doesn't have any built-in error checking. So, you don't know if you got all the bits or not. As such, it is not the right tool for the job. Instead, 'reaom' (read optical media) from the wodim package is what you should be using. It has built-in error checking. Similarly, if you want to burn your newly creating ISO, stay away from 'dd', and use: wodim -v -eject /path/to/image.iso
This is sample output - yours may be different.
59

readom dev=/dev/scd0 f=/path/to/image.iso

atoponce · 2009-03-08 13:21:23 27
Make directory including intermediate directories

This will create the intermediate directories that do not exist. I did not know about this for a long time.
This is sample output - yours may be different.
59

mkdir -p a/long/directory/path

tjweir · 2009-02-07 15:26:27 41
Multiple variable assignments from command output in BASH

This version uses read instead of eval.
This is sample output - yours may be different.
58

read day month year <<< $(date +'%d %m %y')

putnamhill · 2011-07-29 15:05:19 28
Define a quick calculator function

defines a handy function for quick calculations from cli. once defined: ? 10*2+3 Show Sample Output
This is sample output - yours may be different.
```
23?
```
58

? () { echo "$*" | bc -l; }

fizz · 2009-06-28 20:15:30 30

Stream YouTube URL directly to mplayer.

This is the result of a several week venture without X. I found myself totally happy without X (and by extension without flash) and was able to do just about anything but watch YouTube videos... so this a the solution I came up with for that. I am sure this can be done better but this does indeed work... and tends to work far better than YouTube's ghetto proprietary flash player ;-) Replace $i with any YouTube ID you want and this will scrape the site for the _real_ URL to the full quality .FLV file on Youtube's server and will then will hand that over to mplayer (or vlc or whatever you want) to be streamed. In some browsers you can replace $i with just a % or put this in a shell script so all YouTube IDs can be handed directly off to your media player of choice for true streaming without the need for Flash or a downloader like clive. (I do however fully recommend clive if you wish to archive videos instead of streaming them) If any interest is shown I would be more than happy to provide similar commands for other sites. Most streaming flash players use similar logic to YouTube. Edit: 05/03/2011 - Updated line to work with current YouTube. It could be a lot prettier but I will probably follow up with another update when I figure out how to get rid of that pesky Grep. Sed should take that syntax... but it doesn't. Original (no longer working) command: mplayer -fs $(echo "http://youtube.com/get_video.php?$(curl -s $youtube_url | sed -n "/watch_fullscreen/s;.*$video_id.\+$&title.*;\1;p")") Show Sample Output

This is sample output - yours may be different.

MPlayer SVN-r32999-4.4.5 (C) 2000-2011 MPlayer Team

Playing http://v3.lscache2.c.youtube.com/videoplayback?sparams=id%2Cexpire%2Cip%2Cipbits%2Citag%2Calgorithm%2Cburst%2Cfactor&fexp=901031%2C907508%2C900304&algorithm=throttle-factor&itag=34&ipbits=8&burst=40&sver=3&signature=97D6F8D1A948EF2451FD4F093ECA7EF3795EE424.73F2B07D5F478ACEAFCEAC98E7BF2623FEED20EC&expire=1299384000&key=yt1&ip=97.0.0.0&factor=1.25&id=f2ecb156675a27ec.
Resolving v3.lscache2.c.youtube.com for AF_INET6...

Couldn't resolve name for AF_INET6: v3.lscache2.c.youtube.com
Resolving v3.lscache2.c.youtube.com for AF_INET...
Connecting to server v3.lscache2.c.youtube.com[74.125.15.14]: 80...

Cache size set to 320 KBytes
Cache fill: 19.54% (64036 bytes)   

libavformat file format detected.
[flv @ 0x2acf540] Estimating duration from bitrate, this may be inaccurate
[lavf] stream 0: video (h264), -vid 0
[lavf] stream 1: audio (aac), -aid 0
VIDEO:  [H264]  640x360  0bpp  24.000 fps  557.2 kbps (68.0 kbyte/s)
Clip info:
 duration: 162
 starttime: 0
 totalduration: 162
 width: 640
 height: 360
 videodatarate: 544
 audiodatarate: 97
 totaldatarate: 649
 framerate: 24
 bytelength: 13120260
 canseekontime: true
 sourcedata: B4A7D0F03HH1299359484777471
 purl: 
 pmsg: 
==========================================================================
Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
Selected video codec: [ffh264] vfm: ffmpeg (FFmpeg H.264)
==========================================================================
==========================================================================
Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
AUDIO: 44100 Hz, 2 ch, s16le, 99.0 kbit/7.02% (ratio: 12379->176400)
Selected audio codec: [ffaac] afm: ffmpeg (FFmpeg AAC (MPEG-2/MPEG-4 Audio))
==========================================================================
[AO OSS] audio_setup: Can't open audio device /dev/dsp: Device or resource busy
AO: [alsa] 44100Hz 2ch s16le (2 bytes per sample)
Starting playback...
Movie-Aspect is 1.78:1 - prescaling to correct movie aspect.
VO: [xv] 640x360 => 640x360 Planar YV12  [fs]
A:   2.4 V:   2.4 A-V: -0.000 ct:  0.000   0/  0 19% 15%  0.4% 7 0 47%

i="8uyxVmdaJ-w";mplayer -fs $(curl -s "http://www.youtube.com/get_video_info?&video_id=$i" | echo -e $(sed 's/%/\\x/g;s/.*$v[0-9]\.lscache.*$/http:\/\/\1/g') | grep -oP '^[^|,]*')

lrvick · 2009-03-09 03:57:44 59

Remove all but one specific file
This is sample output - yours may be different.
57

rm -f !(survivior.txt)

RanyAlbeg · 2010-09-26 04:50:55 27
Easily search running processes (alias).

Show Sample Output
This is sample output - yours may be different.
```
ps? ruby

13687 s000  S+     0:06.91 ruby script/server
13693 s001  R+     0:00.00 grep ruby
```
57

alias 'ps?'='ps ax | grep '

fzero · 2009-02-05 13:36:37 52
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What's this?

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execute a command in case of success or execute a command in case of failure

Which processes are listening on a specific port (e.g. port 80)

swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

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" }

list block devices

Shows all block devices in a tree with descruptions of what they are.

macOS: Save disk space by moving apps to external drives

Because Mac app bundles contain everything in one place, it makes running them from anywhere, including from a device such as a USB flash drive or external HDD, possible. So if your Mac has a mere 256GB of storage (as mine does), you can free up large quantities of disk space by storing apps like, say, Xcode on external devices.

Use bash history with process substitution

Bash has a great history system of its commands accessed by the ! built-in history expansion operator (documented elsewhere on this site or on the web). You can combine the ! operator inside the process redirection

Hardlink all identical files in the current directory (regain some disk space)

Meaning of switches (see man page too): v verbose p ignore mode (permissions) o ignore owner, group t ignore time of modification Disadvantage: If you modify any linked file, this will propagate to all other files which occupy the same space.

get diskusage of files modified during the last n days

get diskusage of files (in this case logfiles in /var/log) modified during the last n days: $ sudo find /var/log/ -mtime -n -type f | xargs du -ch n -> last modified n*24 hours ago Numeric arguments can be specified as +n for greater than n, -n for less than n, n for exactly n. => so 7*24 hours (about 7 days) is -7 $ sudo find /var/log/ -mtime -7 -type f | xargs du -ch | tail -n1

SSH Copy ed25519 key into your host

Position the cursor under the current directory line

In case you're like me and like your commands to start on clean lines, especially when you're deep into a 10-level directory tree. This can be added to .bashrc.

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