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Remove all .svn folders inside a folder
This is sample output - yours may be different.
-1

find . -name "\.svn" -exec rm -rf {} ";"

caiosba · 2009-05-14 12:02:25 9
search for a file in PATH

search argument in PATH accept grep expressions without args, list all binaries found in PATH Show Sample Output
This is sample output - yours may be different.
```
$ sepath noo
/usr/openwin/bin/ttsnoop
/usr/sbin/snoop
$ sepath ^ps$
/bin/ps
/usr/bin/ps
/usr/ucb/ps
```
-1

function sepath { echo $PATH |tr ":" "\n" |sort -u |while read L ; do cd "$L" 2>/dev/null && find . $ ! -name . -prune $ $ -type f -o -type l $ 2>/dev/null |sed "s@^\./@@" |egrep -i "${*}" |sed "s@^@$L/@" ; done ; }

mobidyc · 2009-09-11 15:03:22 5

Function that searchs a process by its name and shows in the terminal. * Shows the Header for reference * Hides the process 'grep' from the list * Case sensitive Show Sample Output

-1

psg(){ ps aux | grep -v grep | egrep -e "$1|USER"; }

ivanalejandro0 · 2014-12-31 22:27:27 9

(tcsh alias)Reverse an IPv4 address. It is useful to looking the address up in DNSBL.

For 'bash' function ip4rev() { echo $@ | sed 's/^$[0-9]*$\.$[0-9]*$\.$[0-9]*$\.$[0-9]*$/\4.\3.\2.\1/'; } Show Sample Output
This is sample output - yours may be different.
```
% ip4rev '192.0.2.34'
34.2.0.192

% dig +sh a `ip4rev 127.0.0.2`.zen.spamhaus.org.
127.0.0.2
127.0.0.4
127.0.0.10
```
-1

alias ip4rev "echo \!* | sed 's/^$[0-9]*$\.$[0-9]*$\.$[0-9]*$\.$[0-9]*$/\4.\3.\2.\1/'"

azumakuniyuki · 2009-02-09 17:00:03 10
Describe differences between files
This is sample output - yours may be different.
-1

comm --nocheck-order -31

dullgiulio · 2011-06-02 19:17:46 7
Find the biggest files

Show the top file size in human readable form
This is sample output - yours may be different.
-1

find -type f | xargs -I{} du -s "{}" | sort -rn | head | cut -f2 | xargs -I{} du -sh "{}"

glaudiston · 2011-01-04 11:10:56 3
Save your webcam to file
This is sample output - yours may be different.
-1

cvlc "v4l2:///dev/video0" --sout "#transcode{vcodec=mp2v,vb=800,scale=0.25,acodec=none}:file{mux=mpeg1,dst=/PATH/TO/OUTPUT/FILE}"

bitbasher · 2011-08-21 14:25:24 5
Emulate sleep in DOS/BAT

In the vein of "can you do it better", here is my take on using "ping" to emulate sleep in a DOS/BAT script. If one can use ping at all then the multicast address will be valid but will not respond. By doing only one ping (-n 1) and setting a timeout in milliseconds (-w 10000) you have a fairly accurate timer. This example gives about a 10 second sleep.
This is sample output - yours may be different.
-1

ping -n 1 -w 10000 224.0.0.0

DocGyver · 2009-08-26 02:25:07 9
calculate the total size of files in specified directory (in Megabytes)

the command will not include hidden files Show Sample Output
This is sample output - yours may be different.
```
$ls -l | awk 'BEGIN { SUM=0 } { SUM+=$5 } END { print SUM/1024/1024"M" }'
11.35349M
```
-1

ls -l directory | awk 'BEGIN { SUM=0 } { SUM+=$5 } END { print SUM/1024/1024"M" }'

emacs · 2010-06-04 01:51:04 3
Reducing image size

Reduces the size of images.
This is sample output - yours may be different.
-1

convert -quality 40% original_image reduced_image

tsudot · 2010-08-08 03:50:30 5
Get current stable kernel version string from kernel.org
This is sample output - yours may be different.
-1

curl -s kernel.org | grep '<strong>' | head -3 | tail -1 | cut -d'>' -f3 | cut -d'<' -f1

mdix · 2012-06-15 21:28:42 22
Google text-to-speech in mp3 format
This is sample output - yours may be different.
-1

text-to-speech

girao · 2014-09-18 01:25:06 8
search for a file in PATH

Searches in order of the directories of $PATH. Stops after finding the entry; looks for only that fileName. Works in Bourne, Korn, Bash and Z shells. Show Sample Output
This is sample output - yours may be different.
```
/usr/local/bin/fileName
```
-1

for L in `echo :$PATH | tr : '\n'`; do F=${L:-"."}/fileName; if [ -f ${F} -o -h ${F} ]; then echo ${F}; break; fi; done

arcege · 2009-09-11 16:14:36 3
ffmpeg vhook imlib2.so
This is sample output - yours may be different.
-1

ffmpeg -i input.flv -vhook '/usr/lib/vhook/imlib2.so -c white -x 250 -y H+(-1.8*N+80) -t Hallo! -A max(0,255-exp(N/16))' -sameq -acodec copy output.flv

opexxx · 2009-10-06 07:08:02 3
Find the biggest files
This is sample output - yours may be different.
-1

find -type f -exec du -sh {} + | sort -rh | head

depesz · 2011-01-04 11:38:29 5
Find and replace

You can replace "." with your folder
This is sample output - yours may be different.
-1

find . -name '*.txt' -exec mv {} {}.sh \ ;

wilbercarmona · 2011-06-02 23:47:19 3
Generat a Random MAC address

I liked vaporub's suggestion, here a little simplification of the sed command.
This is sample output - yours may be different.
-1

MAC=$((date +'%Y%m%d%H%M%S%N'; cat /proc/interrupts) | md5sum | sed -r 's/(..)/\1:/g' | cut -d: -f 1-6)

jazznjam · 2011-07-14 13:11:50 3
A simple way find total Memory capacity of the system

Show Sample Output
This is sample output - yours may be different.
```
Memory: 192 GB
```
-1

echo "Memory:" $(dmidecode --type memory | grep " MB" | awk '{sum += $2; a=sum/1024} END {print a}') "GB"

bp · 2014-02-18 06:20:34 9
Store Host IP in variable
This is sample output - yours may be different.
-1

export IP="$(hostname -I | awk '{print $1}')"

wuseman1 · 2021-08-10 03:48:21 221
Reducing image size

You can also specify width and height of the resized image (in pixels), as an alternative to using a percentage.
This is sample output - yours may be different.
-1

convert example.png -resize 100x100 output.png

dbbolton · 2010-08-08 16:40:21 3
Find redirection and grep

You can find every file with png extension and redirect its output to file. Later you can find a string inside the file.
This is sample output - yours may be different.
-1

find . -name "*.png" | tee images.txt | grep book

wilbercarmona · 2011-06-02 23:55:50 4
copy root to new device

preserve all except context and xattr. useful when moving a running system to a new partition.
This is sample output - yours may be different.
-1

cp -dpRx /* /mnt/target/

unixmonkey24812 · 2011-08-22 14:22:01 5
Print full LVM LV paths (for copy&paste)
This is sample output - yours may be different.
-1

vgdisplay -v 2>/dev/null | grep "^ LV Name" | while read A B LVDEV; do echo $LVDEV; done

f4m8 · 2011-12-09 14:57:50 4
Check a nfs mountpoint and force a remount if it does not reply after a given timeout.

Based on the execute with timeout command in this site. A more complex script: #!/bin/sh # This script will check the avaliability of a list of NFS mount point, # forcing a remount of those that do not respond in 5 seconds. # # It basically does this: # NFSPATH=/mountpoint TIMEOUT=5; perl -e "alarm $TIMEOUT; exec @ARGV" "test -d $NFSPATH" || (umount -fl $NFSPATH; mount $NFSPATH) # TIMEOUT=5 SCRIPT_NAME=$(basename $0) for i in $@; do echo "Checking $i..." if ! perl -e "alarm $TIMEOUT; exec @ARGV" "test -d $i" > /dev/null 2>&1; then echo "$SCRIPT_NAME: $i is failing with retcode $?."1>&2 echo "$SCRIPT_NAME: Submmiting umount -fl $i" 1>&2 umount -fl $i; echo "$SCRIPT_NAME: Submmiting mount $i" 1>&2 mount $i; fi done
This is sample output - yours may be different.
-1

NFSPATH=/mountpoint TIMEOUT=5; perl -e "alarm $TIMEOUT; exec @ARGV" "test -d $NFSPATH" || (umount -fl $NFSPATH; mount $NFSPATH)

keymon · 2010-06-04 07:58:53 3
How many lines does the passwd file have?
This is sample output - yours may be different.
-1

cat /etc/passwd | wc -l

wilbercarmona · 2011-06-03 00:05:20 26
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ps -ef | grep PROCESS | grep -v grep | awk '{print $2}' | xargs kill -9

kills all pids matching the search term of "PROCESS". Be careful what you wish for :)

Quick and dirty convert to flash

This converts any media ffmpeg handles to flash. It would actually convert anything to anything, it's based on the file extension. It doesn't do ANY quality control, sizing, etc, it just does what it thinks is best. I needed an flv for testing, and this spits one out easily.

Getting Screen's Copy Buffer Into X's Copy Buffer (on Linux)

This command will let you just type c-a b (which means press 'ctrl' then 'a' then 'b'), and screen will save your copy buffer to /tmp/screen-exchange, and then execute xsel to copy the contents of that file into the system's X clipboard. 1. Install Conrad Parker's xsel from http://www.vergenet.net/~conrad/software/xsel/ 2. Add these lines to your .screenrc # Add cool line to make copying to x clipboard possible. # This binds C-a b to copy screen's copy buffer to the system clipboard. bind b eval writebuf 'exec /bin/sh -c "xsel -i -b < /tmp/screen-exchange"' 'exec /bin/sh -c "killall xsel"' 3. Restart screen. 4. Test it by typing c-a [ to enter copy mode. 5. Select some text using vi movement keys (h, j, k, l, etc...) and starting your selection by hitting the space bar, moving with vi movement keys, and then ending your selection with the space bar. 6. Type C-a b, and screen will use xsel to copy your screen copy buffer to the system's X clipboard buffer. 7. Then you can paste the screen copy buffer into any X program. Note: If you're using Mac OSX, you can use pbcopy instead of xsel. Also Note: The second exec in the .screenrc file, which runs killall on xsel, is necessary, because even when you redirect a file to xsel, xsel waits for you to press ctrl-c to kill it, and have it stop waiting for more input. Since xsel forces screen to wait, and I don't want to press ctrl-c, I send the equivalent of ctrl-c with killall causing xsel to write /tmp/screen-exchange to the X clipboard, and then exit. It's a hack, but it works. If you know how to get this to work without a lame hack leave a comment explaining how.

Monitor all DNS queries seen by the local machine

Summarize Apache Extended server-status to show longest running requests

Ever need to know why Apache is bogging down *right now*? Hate scanning Apache's Extended server-status for the longest running requests? Me, too. That's why I use this one liner to quickly find suspect web scripts that might need review. Assuming the Extended server-status is reachable at the target URL desired, this one-liner parses the output through elinks (rendering the HTML) and shows a list of active requests sorted by longest running request at the bottom of the list. I include the following fields (as noted in the header line): Seconds: How long the request is alive PID: Process ID of the request handler State: State of the request, limited to what I think are the relevant ones (GCRK_.) IP: Remote Host IP making the request Domain: Virtual Host target (HTTP/1.1 Host: header). Important for Virtual Hosting servers TYPE: HTTP verb URL: requested URL being served. Putting this in a script that runs when triggered by high load average can be quite revealing. Can also capture "forgotten" scripts being exploited such as "formmail.pl", etc.

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"

Remove all HTML tags from a file

A shorter version of command #3014, using awk instead of sed. Useful when scraping websites with a script.

Use AWS CLI and JQ to get a list of instances sorted by launch time

Use the AWS CLI tools to generate a list instances, then pipe them to JQ to show only their launch time and instance id. Finally use sort to bring them out in runtime order. Find all those instances you launched months ago and have forgotten about.

Batch rename extension of all files in a folder, in the example from .txt to .md

Same thing using bash built-in features instead of a sub-shell.

Print text string vertically, one character per line.

Define a function $ vert () { echo $1 | grep -o '.'; } Use it to print some column headers $ paste

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