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Remove all backup files in my home directory

I use this simple command for remove all backup files generated usually by editors like Vim and Emacs.
This is sample output - yours may be different.
4

find ~user/ -name "*~" -exec rm {} \;

servermanaged · 2009-05-09 12:55:47 89
Get an IP address out of fail2ban jail

Removes an iptables rule created by fail2ban. This example shows how to remove a rule for an IP from the fail2ban-SSH chain. Can be used for any service monitored by fail2ban. For more on fail2ban, see http://www.fail2ban.org/wiki/index.php/Main_Page
This is sample output - yours may be different.
4

iptables -D fail2ban-SSH -s <ip_address_to_be_set_free> -j DROP

mheadd · 2009-05-08 19:22:15 3
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
Safe Delete

remove file that has sensitive info safely. Overwrites it 33 times with zeros
This is sample output - yours may be different.
2

shred -n33 -zx file; rm file

copremesis · 2009-05-08 19:15:41 8
Remove unused libs/packages

deborphan(1) must be installed.
This is sample output - yours may be different.
0

aptitude remove $(deborphan)

P17 · 2009-05-08 18:51:51 7
en/decrypts files in a specific directory

To decrypt the files replace "ccenrypt" with "ccdecrypt. ccrypt(1) must be installed. It uses the AES (Rijndael) block cipher. To make it handier create an alias.
This is sample output - yours may be different.
4

for a in path/* ; do ccenrypt -K <password> $a; done

P17 · 2009-05-08 18:33:23 6
Edit a script that's somewhere in your path.

Often I need to edit a bash or perl script I've written. I know it's in my path but I don't feel like typing the whole path (or I don't remember the path).
This is sample output - yours may be different.
1

vim `which <scriptname>`

bunedoggle · 2009-05-08 17:21:47 6
Clears Firefox` cache without clicking around
This is sample output - yours may be different.
0

rm_cache() { rm -f $HOME/.mozilla/firefox/<profile>/Cache/* }; alias rmcache='rm_cache'

P17 · 2009-05-08 14:00:42 3
Go to the last directory invoked on command line

During this operation : # mv Joomla_1.5.10-Stable-Full_Package.zip /var/www/joomla/ I invoke /var/www/joomla/ as last command argument. To change in this directory I can use # cd !$ So I go to hob:/var/www/joomla#
This is sample output - yours may be different.
-3

cd !$

servermanaged · 2009-05-08 09:48:14 6
Generate padded numbers 001 002 ... 100
This is sample output - yours may be different.
0

echo 00{1..9} 0{10..99} 100

lv4tech · 2009-05-07 21:08:53 10
Search for files older than 30 days in a directory and list only their names not the full path
This is sample output - yours may be different.
2

find /var/www/html/ -type f -mtime +30 -exec basename {} \;

lv4tech · 2009-05-07 21:05:47 6
Find out which version of linux you are running
This is sample output - yours may be different.
-6

cat /etc/*issue

lv4tech · 2009-05-07 20:53:03 10
Execute multiple commands from history

Assuming that 219,229 and 221 are entries in history, I recall them in a single line for execute multiple commands 219 ifdown wlan0 ... 221 ifup wlan0 ... 229 iwconfig wlan0 mode Managed so the result is execution of # ifdown wlan0 ; iwconfig wlan0 mode Managed ; ifup wlan0
This is sample output - yours may be different.
8

!219 ; !229 ; !221

servermanaged · 2009-05-07 20:51:36 8
Follow the flow of a log file

tailf same as tail -f follow the flow of a log file, showing it in real time to stdout.
This is sample output - yours may be different.
5

tailf file.log

servermanaged · 2009-05-07 20:13:41 6
Search and replace in multiple files and save them with the same names - quickly and effectively!

Yeah, there are many ways to do that. Doing with sed by using a for loop is my favourite, because these are two basic things in all *nix environments. Sed by default does not allow to save the output in the same files so we'll use mv to do that in batch along with the sed. Show Sample Output
This is sample output - yours may be different.
```
No standard output on screen... just hit and boom. So, by the rule of the thumb first create a backup and then execute  or try to execute on some dummy files first.
```
-4

for files in $(ls -A directory_name); do sed 's/search/replaced/g' $files > $files.new && mv $files.new $files; done;

bassu · 2009-05-07 20:13:07 48
Find which version of Linux You are Running
This is sample output - yours may be different.
-4

lsb_release -d

tebeka · 2009-05-07 16:19:04 9
Ultra shortcut for ssh root@

When you have to manage lot of servers, it's boring to type ssh root@myhost for each connection. Now you can type juste "s someting" and you are connected. You can too add bash_completion script to complet with tab the name of your servers. This will be the next tips from me ;) Show Sample Output
This is sample output - yours may be different.
```
user@localhost:~$ s myhost
Last login: Mon May  4 15:16:18 2009 from 10.40.29.72
[root@myhost ~]#
```
-20

alias s='ssh -l root'

GouNiNi · 2009-05-07 15:57:12 11
Run a long job and notify me when it's finished

You will need libnotify-bin for this to work: sudo aptitude install libnotify-bin
This is sample output - yours may be different.
25

./my-really-long-job.sh && notify-send "Job finished"

root · 2009-05-07 15:50:27 16
Safely store your gpg key passphrase.

From time to time one forgets either thier gpg key or other passphrases. This can be very problematic in most cases. But luckily there's this script. Its based off of pwsafe which is a unix commandline program that manages encrypted password databases. For more info on pwsafe visit, http://nsd.dyndns.org/pwsafe/. What this script does is it will help you store all your passphrases for later on and allow you to copy it to your clipboard so you can just paste it in, all with one password. Pretty neat no? You can find future releases of this and many more scripts at The Teachings of Master Denzuko - denzuko.wordpress.com. Show Sample Output
This is sample output - yours may be different.
```
Enter passphrase for $HOME/.pwsafe.dat: _
```
0

pwsafe -qa "gpg keys"."$(finger `whoami` | grep Name | awk '{ print $4" "$5 }')"

denzuko · 2009-05-07 14:49:56 4
Expand shell variables in sed scripts

With this command you can use shell variables inside sed scripts. This is useful if the script MUST remain in an external file, otherwise you can simply use an inline -e argument to sed.
This is sample output - yours may be different.
-1

expanded_script=$(eval "echo \"$(cat ${sed_script_file})\"") && sed -e "${expanded_script}" your_input_file

giuseppe_rota · 2009-05-07 14:21:14 5
Random line from bash.org (funny IRC quotes)

bash.org is a collection of funny quotes from IRC. WARNING: some of the quotes contain "adult" jokes... may be embarrassing if your boss sees them... Thanks to Chen for the idea and initial version! This script downloads a page with random quotes, filters the html to retrieve just one liners quotes and outputs the first one. Just barely under the required 255 chars :) Improvment: You can replace the head -1 at the end by: awk 'length($0)>0 {printf( $0 "\n%%\n" )}' > bash_quotes.txt which will separate the quotes with a "%" and place it in the file. and then: strfile bash_quotes.txt which will make the file ready for the fortune command and then you can: fortune bash_quotes.txt which will give you a random quote from those in the downloaded file. I download a file periodically and then use the fortune in .bashrc so I see a funny quote every time I open a terminal. Show Sample Output
This is sample output - yours may be different.
```
<Lev> have you SEEN the people who wear the I LOVE LINUX T-shirts....that does more damage to the OS than a billion microsoft blue-screens
```
7

curl -s http://bash.org/?random1|grep -oE ".*.*"|grep -oE ""|sed -e 's/<\/p>/\n/g' -e 's///g' -e 's///g'|perl -ne 'use HTML::Entities;print decode_entities($_),"\n"'|head -1

Iftah · 2009-05-07 13:13:21 17
Which fonts are installed?

See all fonts installed in your system Show Sample Output
This is sample output - yours may be different.
```
Andale Mono
Arab
Arial
Arial Black
AR PL UMing CN
AR PL UMing HK
AR PL UMing TW
AR PL UMing TW MBE
Balker
Bitstream Charter
Bitstream Vera Sans
Bitstream Vera Sans Mono
Bitstream Vera Serif ....
```
5

fc-list | cut -d ':' -f 1 | sort -u

kayowas · 2009-05-07 12:57:58 15
Cloning hard disks over the network:

This is a bit to bit copy so if you have a 500GB hard disk it will take a long time even if have Gigabit Ethernet
This is sample output - yours may be different.
-1

Boot up destination machine with Knoppix live CD and run nc -l -p 9000 | dd of=/dev/sda Then on the master dd if=/dev/sda | nc <dest-ip> 9000 You can monitor bandwidth usage to see progress: nload eth0 -u M

lv4tech · 2009-05-07 05:26:58 6
Start a file browser in the current directory

This opens up nautilus in the current directory, which is useful for some quick file management that isn't efficiently done from a terminal.
This is sample output - yours may be different.
-10

screen -d -m nautilus --no-desktop `pwd`

windsurfer · 2009-05-07 00:49:07 14
sync a directory of corrupted jpeg with a source directory

Find all corrupted jpeg in the current directory, find a file with the same name in a source directory hierarchy and copy it over the corrupted jpeg file. Convenient to run on a large bunch of jpeg files copied from an unsure medium. Needs the jpeginfo tool, found in the jpeginfo package (on debian at least).
This is sample output - yours may be different.
0

for i in *jpg; do jpeginfo -c $i | grep -E "WARNING|ERROR" | cut -d " " -f 1 | xargs -I '{}' find /mnt/sourcerep -name {} -type f -print0 | xargs -0 -I '{}' cp -f {} ./ ; done

vincentp · 2009-05-07 00:30:36 4
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Print all lines between two line numbers

This command uses awk(1) to print all lines between two known line numbers in a file. Useful for seeing output in a log file, where the line numbers are known. The above command will print all lines between, and including, lines 3 and 6.

back ssh from firewalled hosts

host B (you) redirects a modem port (62220) to his local ssh. host A is a remote machine (the ones that issues the ssh cmd). once connected port 5497 is in listening mode on host B. host B just do a ssh 127.0.0.1 -p 5497 -l user and reaches the remote host'ssh. This can be used also for vnc and so on.

Archive all SVN repositories in platform indepenent form

This command dumps all SVN repositories inside of folder "repMainPath" (not recursively) to the folder "dumpPath", where one dump file will be created for each SVN repository.

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"

defragment files

Thanks to flatcap for optimizing this command. This command takes advantage of the ext4 filesystem's resistance to fragmentation. By using this command, files that were previously fragmented will be copied / deleted / pasted essentially giving the filesystem another chance at saving the file contiguously. ( unlike FAT / NTFS, the *nix filesystem always try to save a file without fragmenting it ) My command only effects the home directory and only those files with your R/W (read / write ) permissions. There are two issues with this command: 1. it really won't help, it works, but linux doesn't suffer much (if any ) fragmentation and even fragmented files have fast I/O 2. it doesn't discriminate between fragmented and non-fragmented files, so a large ~/ directory with no fragments will take almost as long as an equally sized fragmented ~/ directory The benefits i managed to work into the command: 1. it only defragments files under 16mb, because a large file with fragments isn't as noticeable as a small file that's fragmented, and copy/ delete/ paste of large files would take too long 2. it gives a nice countdown in the terminal so you know how far how much progress is being made and just like other defragmenters you can stop at any time ( use ctrl+c ) 3. fast! i can defrag my ~/ directory in 11 seconds thanks to the ramdrive powering the command's temporary storage bottom line: 1. its only an experiment, safe ( i've used it several times for testing ), but probably not very effective ( unless you somehow have a fragmentation problem on linux ). might be a placebo for recent windows converts looking for a defrag utility on linux and won't accept no for an answer 2. it's my first commandlinefu command

Add 10 random unrated songs to xmms2 playlist

If you're like me and want to keep all your music rated, and you use xmms2, you might like this command. I takes 10 random songs from your xmms2 library that don't have any rating, and adds them to your current playlist. You can then rate them in another xmms2 client that supports rating (I like kuechenstation). I'm pretty sure there's a better way to do the grep ... | sed ... part, probably with awk, but I don't know awk, so I'd welcome any suggestions.

a function to find the fastest DNS server

http://public-dns.info gives a list of online dns servers. you need to change the country in url (br in this url) with your country code. this command need some time to ping all IP in list.

Find the package that installed a command

Find status of all symlinks

The symlinks command can show status of all symbolic links, including which links are dangling, which symlinks point to files on other file systems, which symlinks use ../ more than necessary, which symlinks are messy (e.g. having too many slashes or dots), etc. Other useful things it can do include removing all dangling links (-d) and converting absolute links to relative links (-c). The path given must be an absolute path (which is why I used $(pwd) in the example command).

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"

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