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Replace strings in files

Replace the word 'war' to word 'peace' in every file in the current directory.
This is sample output - yours may be different.
0

sed -i -e 's/war/peace/g' *

tiagofischer · 2010-01-02 13:16:35 3
Shorten url using bit.ly API

It uses curl --url-encode to encode long URLs *properly* and parses XML with xmlstarlet. If ~/.bitlyrc were to contain login:apikey then a script could read the apiKey and login from ~/.bitlyrc like so: login=$(sed 's/:.*//' < $HOME/.bitlyrc) apikey=$(sed 's/[^:]*://' < $HOME/.bitlyrc) curl -s --data-urlencode 'longUrl='$1 --data-urlencode 'login='$login --data-urlencode 'apiKey='$apikey 'http://api.bit.ly/shorten?version=2.0.1&format=xml' | xmlstarlet sel -T -t -m "//shortUrl" -v "." | line Show Sample Output
This is sample output - yours may be different.
```
[16:58][~]$ bitly http://google.com
http://bit.ly/4sloPA
```
0

curl -s --data-urlencode 'longUrl='$1 --data-urlencode 'login='$login --data-urlencode 'apiKey='$apikey 'http://api.bit.ly/shorten?version=2.0.1&format=xml' | xmlstarlet sel -T -t -m "//shortUrl" -v "." | line

jnash · 2010-01-02 11:32:42 3
cd up a number of levels

Instead of typing "cd ../../.." you can type ".. 3". For extremely lazy typists, you can add this alias: alias ...=".. 2" ....=".. 3" - so now you can write just .... !!! NB the .. function needs to be "source"d or included in your startup scripts, perhaps .bashrc.
This is sample output - yours may be different.
4

function ..(){ for ((j=${1:-1},i=0;i<j;i++));do builtin cd ..;done;}

bhepple · 2010-01-02 08:36:12 12
convert wav into mp3 using lame
This is sample output - yours may be different.
1

lame -V2 rec01.wav rec01.mp3

eastwind · 2010-01-01 06:09:46 4
Chage default shell for all users [FreeBSD]

This command will set bash as the default shell for all users in a FreeBSD system.
This is sample output - yours may be different.
6

cd /usr/home && for i in *;do chsh -s bash $i;done

casidiablo · 2009-12-31 18:48:53 6
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
Display _something_ when an X app fails

When you run an X program from a terminal you can see any errors. But when it's run from another X program (eg from a menu item, from your fluxbox 'keys' file etc) it might just die and you see nothing (except perhaps in .xsession-errors). Instead, launch it via this command and you'll see the termination status, stderr and stdout. eg: "xlaunch firefox" or "xlaunch 'echo stdout; echo stderr >&2; false'": 'echo stdout; echo stderr >&2; false' failed with error 1 STDERR: stderr STDOUT: stdout
This is sample output - yours may be different.
1

xlaunch(){ T=/tmp/$$;sh -c "$@" >$T.1 2>$T.2;S=$?;[ $S -ne 0 ]&&{ echo -e "'$@' failed with error $S\nSTDERR:\n$(cat $T.2)\nSTDOUT:\n$(cat $T.1)\n"|xmessage -file -;};rm -f $T.1 $T.2;}

bhepple · 2009-12-31 06:59:56 3
Setup a persistant SSH tunnel w/ pre-shared key authentication

This creates a persistent ssh -i /path/to/key -ND local-IP:PORT User@Server connection. You may have to install autossh. -f puts in daemon mode. if you are having trouble, try it without -f.
This is sample output - yours may be different.
4

autossh -f -i /path/to/key -ND local-IP:PORT User@Server

fotoflo · 2009-12-31 06:10:03 5
external projector for presentations

i spent way too many hours trying to fiddle with /etc/X11/xorg.conf trying to hook up various external projectors. too bad i didn't know this would solve all my problems.
This is sample output - yours may be different.
8

xrandr --auto

kanzure · 2009-12-30 18:52:02 9
mount an iso

mounts an ISO file to a directory on the target file system
This is sample output - yours may be different.
6

mount -o loop -t iso9660 my.iso /mnt/something

kanzure · 2009-12-30 18:49:30 4
climagic's New Year's Countdown clock

This is the 140 character long new year's countdown timer that was posted to the climagic account on twitter and identi.ca. There are saner ways of doing this of course, but probably none of those would fit. Uses the figlet command, but of course you can replace figlet with just echo if you want. Show Sample Output
This is sample output - yours may be different.
```
 _ ____  _____ ___   ___   __
/ |___ \|___ // _ \ ( _ ) / /_
| | __) | |_ \ (_) |/ _ \| '_ \
| |/ __/ ___) \__, | (_) | (_) |
|_|_____|____/  /_/ \___/ \___/
```
6

while V=$((`date +%s -d"2010-01-01"`-`date +%s`));do if [ $V == 0 ];then figlet 'Happy New Year!';break;else figlet $V;sleep 1;clear;fi;done

deltaray · 2009-12-30 18:42:38 11
Increase mplayer maximum volume

use '0' and '9' to increase/decrease volume. this is useful on laptops with low speaker volume.
This is sample output - yours may be different.
7

mplayer dvd:// -softvol -softvol-max 500

kanzure · 2009-12-30 18:19:44 9
Find and print pattern location from all files on command line from directory and its sub directories.

The command will help to print the location of the pattern. Above command will print all the files which contain variable "$foo" along with line containing that pattern. Specify pattern after "grep"
This is sample output - yours may be different.
-1

find . -exec grep $foo {} \; -print

linuxgeek · 2009-12-30 17:41:44 4
monitor network traffic and throughput in real time

see http://iptraf.seul.org/ for all kinds of documentation and screenshots
This is sample output - yours may be different.
4

iptraf

linuxrawkstar · 2009-12-30 15:41:21 4
Get your public ip

Requires Python; doesn't require a specific server to return your IP.
This is sample output - yours may be different.
-11

python -c "import socket; s=socket.socket(socket.AF_INET, socket.SOCK_DGRAM); s.connect(('google.com', 80)); print s.getsockname()[0]"

whiteinge · 2009-12-29 19:17:03 10
generate random password

eliminates "l" and "o" characters change length by changing 'x' here: cut -c 1-x Show Sample Output
This is sample output - yours may be different.
```
d6pd9625
```
-3

openssl rand -base64 1000 | tr "[:upper:]" "[:lower:]" | tr -cd "[:alnum:]" | tr -d "lo" | cut -c 1-8 | pbcopy

_eirik · 2009-12-29 17:18:25 31
Display the output of a command from the first line until the first instance of a regular expression.

Slightly simpler version of previous sed command that does the same thing. In this case, the output will stop at the command, and the entire command will be terminated as well, instead of proceeding through the whole file.
This is sample output - yours may be different.
1

command | sed '/regex/q'

taliver · 2009-12-29 14:52:41 3
Check if file is greater than 20 bytes, such as an empty gzip archive

If you gzip an empty file it becomes 20 bytes. Some backup checks i do check to see if the file is greater than zero size (-s flag) but this is no good here. Im sure someone has a better check than me for this? No check to see if file exists before checking it's size.
This is sample output - yours may be different.
-2

BACKUP_FILE_SIZE=`eval ls -l ${BACKUP_FILE} | awk {'print $5'}`; if [ $BACKUP_FILE_SIZE -le 20 ]; then echo "its empty"; else echo "its not empty"; fi

Redrocket · 2009-12-29 08:34:37 3
Empty a file
This is sample output - yours may be different.
6

> foobar.txt

unixmonkey7657 · 2009-12-29 08:08:15 4
Empty a file
This is sample output - yours may be different.
-1

truncate foobar.txt

w216 · 2009-12-29 01:52:12 3
find out how much space are occuipied by files smaller than 1024K (sic) - improved

The original didn't use -print0 which fails on weird file names eg with spaces. The original parsed the output of 'ls -l' which is always a bad idea.
This is sample output - yours may be different.
2

find dir -size -1024k -type f -print0 | du --files0-from - -bc

bhepple · 2009-12-29 01:33:55 3
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
reload config

reload a configuration from .bashrc file Show Sample Output
This is sample output - yours may be different.
```
root@ubuserver:~# source .bashrc
root@ubuserver:~#
```
0

source .bashrc

bbmarek · 2009-12-29 00:14:34 17
Get your public ip
This is sample output - yours may be different.
0

curl -s http://icanhazip.com/

w216 · 2009-12-28 23:00:37 3
Read just the IP address of a device
This is sample output - yours may be different.
0

ifconfig -l | xargs -n1 ipconfig getifaddr 2> /dev/null

w216 · 2009-12-28 22:45:45 3
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What's this?

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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Remove a line from a file using sed (useful for updating known SSH server keys when they change)

remove the host for the .ssh/know_host file

Check whether laptop is running on battery or cable

In my case it was actually like this...

Get decimal ascii code from character

printf treats first char after single ' as numeric equivalent

Command line calculator

This function defines a command line calculator that handles everything pythons math module can handle, e.g. trigonometric functions, sqrt, log, erf, ... (see http://docs.python.org/library/math.html). It even knows about the constants pi and e.

Drop or block attackers IP with null routes

Someone might attack on your system. You can drop attacker IP using IPtables. However, you can use route command to null route unwanted traffic. A null route (also called as blackhole route) is a network route or kernel routing table entry that goes nowhere. Matching packets are dropped (ignored) rather than forwarded, acting as a kind of very limited firewall. The act of using null routes is often called blackhole filtering.

drill holes on image

Detect illegal access to kernel space, potentially useful for Meltdown detection

Based on capsule8 agent examples, not rigorously tested

truncate deleted files from lsof

While the posted solution works, I'm a bit uneasy about the "%d" part. This would be hyper-correct approach: $ lsof|gawk '$4~/txt/{next};/REG.*$deleted$$/{sub(/.$/,"",$4);printf ">/proc/%s/fd/%s\n", $2,$4}' Oh, and you gotta pipe the result to sh if you want it to actually trim the files. ;) Btw, this approach also removes false negatives (OP's command skips any deleted files with "txt" in their name).

Find out current working directory of a process

Copy files from multiple directories into one directory

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