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Remove all files previously extracted from a tar(.gz) file.

xargs deals badly with special characters (such as space, ' and "). To see the problem try this: touch important_file touch 'not important_file' ls not* | xargs rm Parallel https://savannah.nongnu.org/projects/parallel/ does not have this problem.
This is sample output - yours may be different.
-2

tar -tf <file.tar.gz> | parallel rm

unixmonkey8046 · 2010-01-28 08:28:16 3
run command on a group of nodes in parallel

Parallel is from https://savannah.nongnu.org/projects/parallel/ Other examples would be: (echo foss.org.my; echo www.debian.org; echo www.freenetproject.org) | parallel traceroute seq -f %04g 0 9999 | parallel -X rm pict{}.jpg
This is sample output - yours may be different.
3

seq 1 5 | parallel ssh {}.cluster.net uptime

unixmonkey8046 · 2010-01-28 08:18:50 6
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
Insert the last argument of the previous command
This is sample output - yours may be different.
2

<ALT> .

fraktil · 2010-01-28 03:33:31 5
Press a key automatically

Press a key automatically via xvkbd.
This is sample output - yours may be different.
1

while true; do xvkbd -xsendevent -text "\[$KEY]" && sleep 2; done

matthewbauer · 2010-01-28 03:11:10 14
Block all IP addresses and domains that have attempted brute force SSH login to computer

I use iptables. To rate limit connections. Very easy and no ban lists to manage.
This is sample output - yours may be different.
3

/usr/sbin/iptables -I INPUT -p tcp --dport 22 -i eth0 -m state --state NEW -m recent -set

jeffatrackaid · 2010-01-28 00:51:49 3
Extract names and email addresses from LDIF files
This is sample output - yours may be different.
0

grep -E '^(cn|mail):' file.ldif | sed -e 's/^[a-z]*: //'

linuxnetbook · 2010-01-27 22:29:02 4
Erase a word
This is sample output - yours may be different.
6

<CTRL+w>

jslopez · 2010-01-27 22:13:29 25
Erase a word

hit BACKSPACE more than once to delete more words Show Sample Output
This is sample output - yours may be different.
```
$ echo something
<ALT> <BACKSPACE>
$ echo
```
2

<ALT> <BACKSPACE>

wincus · 2010-01-27 19:52:51 4
MAC OS X: audible notification after a long command

I often run some command that takes a while to finish. By putting the say command afterward, I get an audio notification. Please note that this command (say) only works on Mac OS X and not Linux.
This is sample output - yours may be different.
-2

long_command; say I am all done

haivu · 2010-01-27 19:03:01 12
Shell function to create a directory named with the current date, in the format YYYYMMDD.

Creates a directory named with the current date, in the format YYYYMMDD. If you give it a directory name as an argument, it will create the new directory inside the specified directory. This is an alternative to command #1993. Show Sample Output
This is sample output - yours may be different.
```
$ # in '.'
$ dmd
$ ls -l
drwxr-xr-x 2 bchittenden bchittenden 4096 2010-01-27 10:26 20100127
$ # in 'test/asdf/'
$ mkdir -p test/asdf
$ dmd test/asdf
$ ls -l test/asdf
drwxr-xr-x 2 bchittenden bchittenden 4096 2010-01-27 10:29 20100127
```
1

dmd () { ( if [ "$1"x != "x" ]; then cd $1; fi; mkdir `date +%Y%m%d` ) }

bartonski · 2010-01-27 15:53:26 5
Do some Perl learning...

Prerequisites: module Pod::Webserver installed. You can install it typing: sudo perl -MCPAN -e 'install Pod::Webserver' You can replace elinks with your fav browser. For FF: podwebserver& sleep 2; firefox -remote 'openurl( http://127.0.0.1:8020/, new-tab )' If you have Firefox open, this will pop-up the index web in a new tab.
This is sample output - yours may be different.
5

podwebserver& sleep 2; elinks 'http://127.0.0.1:8020'

vlan7 · 2010-01-27 10:57:34 13
Using numsum to sum a column of numbers.

if you, like me, do not have the numsum, this way can do the same. Show Sample Output
This is sample output - yours may be different.
```
1653
```
1

echo $(( $( cat count.txt | tr "\n" "+" | xargs -I{} echo {} 0 ) ))

glaudiston · 2010-01-27 10:02:30 4
Simple Gumblar check command
This is sample output - yours may be different.
1

find filepath -type f -iname "*.html" -o -iname "*.htm" -o -iname "*.php" | xargs grep "Exception\|LGPL\|CODE1"

negima · 2010-01-27 08:43:24 3

Gathering all MAC's in your local network

replace eth0 with your ethernet or wireless network interface. Show Sample Output

sudo arp-scan --interface=eth0 -l

alamati · 2010-01-27 05:36:48 3

delete multiple files with spaces in filenames (with confirmation)

ls -Q will show the filenames in quotes. xargs -p rm will print all the filenames piped from ls -Q and ask for confirmation before deleting the files. without the -Q switch, if we have spaces in names, then the files won't be deleted. Show Sample Output
This is sample output - yours may be different.
```
ls -Q *
"new file"  "new file (another copy)"  "new file (copy)"

ls -Q * | xargs -p rm
rm new file new file (another copy) new file (copy) ?...y
```
1

ls -Q * | xargs -p rm

temp_reg · 2010-01-27 02:46:49 9
Find the fastest server to disable comcast's DNS hijacking

Comcast is an ISP in the United States that has started hijacking DNS requests as a "service" for its customers. For example, in Firefox, one used to be able to do a quick "I'm Feeling Lucky" Google search by typing a single word into the URL field, assuming the word is not an existing domain when surrounded by www.*.com. Comcast customers never receive the correct NX (non-existent domain) error from DNS. Instead, they are shown a page full of advertising. There is a way to "opt out" from their service, but that requires having the account password and the MAC address of your modem handy. For me, it was easier just to set static DNS servers. But the problem is, which ones to choose? That's what this command answers. It'll show you the three _non-hijacked_ Comcast DNS servers that are the shortest distance away. Perhaps you don't have Comcast (lucky you!), but hopefully this command can serve as an example of using netselect to find the fastest server from a list. Note that, although this example doesn't show it, netselect will actually perform the uniq and DNS resolution for you. Requires: netselect, curl, sort, uniq, grep Show Sample Output
This is sample output - yours may be different.
```
Running netselect to choose 3 out of 12 addresses.      
...........................................................................
   53 68.87.69.146
   62 68.87.76.178
  273 68.87.74.162
```
2

sudo netselect -v -s3 $(curl -s http://dns.comcast.net/dns-ip-addresses2.php | egrep -o '[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+' | sort | uniq)

hackerb9 · 2010-01-27 00:03:44 5
Using numsum to sum a column of numbers.

numsum is part of of the num-utils package, which is available in some Linux distros and can also be downloaded at http://suso.suso.org/xulu/Num-utils. It contains about 10 different programs for dealing with numbers from the command line. Obviously you can do a lot of things that the num-utils programs do in awk, sed, bash, perl scripts, but num-utils are there so that you don't have to remember the syntax for more complex operations and can just think: compute the sum, average, boundary numbers, etc. Show Sample Output
This is sample output - yours may be different.
```
15
```
5

numsum count.txt

deltaray · 2010-01-26 21:53:18 9
Give to anyone a command to immediatly find a particular part of a man.

Example : LC_ALL=C man less | less +/ppattern
This is sample output - yours may be different.
6

man <COMMAND> | less +'/pattern'

sputnick · 2010-01-26 20:50:00 3
Optimize PDF documents
This is sample output - yours may be different.
12

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.pdf input.pdf

alamati · 2010-01-26 19:00:01 22
kde4 lock screen command

If you wish to launch the kde4 screen saver without the password prompt to exit, use this command: qdbus org.freedesktop.ScreenSaver /ScreenSaver org.freedesktop.ScreenSaver.SetActive True Also can be done with: /usr/lib/kde4/libexec/kscreenlocker --forcelock
This is sample output - yours may be different.
3

qdbus org.freedesktop.ScreenSaver /ScreenSaver Lock

starchox · 2010-01-26 17:50:10 5
Recursively grep for string and format output for vi(m)

This is a big time saver for me. I often grep source code and need to edit the findings. A single highlight of the mouse and middle mouse click (in gnome terminal) and I'm editing the exact line I just found. The color highlighting helps interpret the data.
This is sample output - yours may be different.
2

mgc() { grep --exclude=cscope* --color=always -rni $1 . |perl -pi -e 's/:/ +/' |perl -pi -e 's/^(.+)$/vi $1/g' |perl -pi -e 's/:/ /'; }

stinkerweed999 · 2010-01-26 17:00:01 4
Recursively grep thorugh directory for string in file.

Print line numbers also, so you don't have to search through the files once its open for the string you already grepped for.
This is sample output - yours may be different.
2

grep -rni string dir

stinkerweed999 · 2010-01-26 16:34:06 3
Show File System Hierarchy

Curious about differences between /bin, /usr/bin, and /usr/local/bin? What should be in the /sbin dir? Try this command to find out. Tested against Red Hat & OS X
This is sample output - yours may be different.
95

man hier

haivu · 2010-01-26 16:31:05 30
Recursively grep thorugh directory for string in file.

-R, -r, --recursive Read all files under each directory, recursively; this is equivalent to the -d recurse option.
This is sample output - yours may be different.
8

grep -r -i "phrase" directory/

TheFox · 2010-01-26 16:27:00 8
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Get AWS temporary credentials ready to export based on a MFA virtual appliance

You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials

Quickly build ulimit command from current values

It is helpful to know the current limits placed on your account, and using this shortcut is a quick way to figuring out which values to change for optimization or security. Alias is: $ alias ulimith="command ulimit -a|sed 's/^.*$[a-z]$)$.*$$/-\1\2/;s/^/ulimit /'|tr '\n' ' ';echo" Here's the result of this command: $ ulimit -c 0 -d unlimited -e 0 -f unlimited -i 155648 -l 32 -m unlimited -n 8192 -p 8 -q 819200 -r 0 -s 10240 -t unlimited -u unlimited -v unlimited -x unlimited $ ulimit -a core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 155648 max locked memory (kbytes, -l) 32 max memory size (kbytes, -m) unlimited open files (-n) 8192 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 10240 cpu time (seconds, -t) unlimited max user processes (-u) unlimited virtual memory (kbytes, -v) unlimited file locks (-x) unlimited

dd with progress bar

piping through 'pv' shows a simple progress/speed bar for dd. This is a replacement for my otherwise favorite 'while :;do killall -USR1 dd;sleep 1;done'

Determine command type (alias, keyword, function, builtin, or file)

Prints a string indicating whether a command is an alias, keyword, function, builtin, or file. I have used this in my BASH scripts to allow an external parameter to define which function to run, and ensure that it is a valid function that can indeed be run.

View Processeses like a fu, fu

Shows a less detailed output, made only of the process tree and their pids.

Swap a file or dir with quick resotre

This lets you replace a file or directory and quickly revert if something goes wrong. For example, the current version of a website's files are in public_html. Put a new version of the site in public_html~ and execute the command. The names are swapped. If anything goes wrong, execute it again (up arrow or !!).

See OpenVZ Container id's of top 10 running processes by %cpu

This command will list the PID, VEID, and Name of the 10 highest cpu using processes on a openvz host. You must have vzpid installed.

Calculate days on which Friday the 13th occurs (inspired from the work of the user justsomeguy)

Friday is the 5th day of the week, monday is the 1st. Output may be affected by locale.

Tweak system files without invoking a root shell

only for sudo-style systems. Use this construct instead of I/O re-directors ``>'' or ``>>'' because sudo only elevates the commands and *not* the re-directors. ***warning: remember that the `tee` command will clobber file contents unless it is given the ``-a'' argument Also, for extra security, the "left" command is still run unprivileged.

pipe output of a command to your clipboard

In turn you can get the contents of your clipboard by typing xsel by itself with no arguments: $ xsel This command requires you to install the xsel utility which is free

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