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Show the UUID of a filesystem or partition

Shows the UUID of a filesystem or partition that can be used in kernel root options and in fstab. Run it without the -u option to generate more information. eg: ~/ sudo vol_id /dev/sda2 ID_FS_USAGE=other ID_FS_TYPE=swap ID_FS_VERSION=2 ID_FS_UUID=27fca13d-97b7-4d28-882c-6d03353f0a82 ID_FS_UUID_ENC=27fca13d-97b7-4d28-882c-6d03353f0a82 ID_FS_LABEL= ID_FS_LABEL_ENC= Show Sample Output
This is sample output - yours may be different.
```
c0cddfdb-8a0b-4b45-afb1-b904825bf31d
```
3

sudo vol_id -u /dev/sda1

agentk · 2009-04-30 01:40:58 5
Change wallpaper for xfce4 >= 4.6.0

Simply changes the wallpaper of xfce4 from the command line. Not for multiple displays.
This is sample output - yours may be different.
3

xfconf-query -c xfce4-desktop -p /backdrop/screen0/monitor0/image-path -s <image-file>

TheMightyBuzzard · 2009-04-30 01:40:52 11
send Everyone on your machine some love

This works just like write or wall ... cept one thing the sender is anonymous ... if you really want to drive everyone insane replace echo \"The Matrix has you...\" with cat /dev/urandom nice one to do on April fool's day Show Sample Output
This is sample output - yours may be different.
```
The Matrix has you... (on all writable ttys)
```
-12

w | egrep -v '(load|FROM)' | awk '{print $2}' | sed 's/^/tty/' | awk '{print "echo \"The Matrix has you...\" >> /dev/" $1}' | bash

copremesis · 2009-04-29 22:04:56 10
journaling directories

use today's time stamp to make a unique directory for today or an hour ago ... Show Sample Output
This is sample output - yours may be different.
```
Wed_Apr_29_15_53_58_CDT_2009
```
-4

mkdir `date | sed 's/[: ]/_/g'`

copremesis · 2009-04-29 21:28:45 36
Avoiding history file to be overwritten

If histappend options is set in bash, the file .bash_history will not be overwrite and history list is append to it.
This is sample output - yours may be different.
4

shopt -s histappend

servermanaged · 2009-04-29 19:49:53 4
Prevent non-root users from logging in

Also with optional message: echo "no login for you" > /etc/nologin (This doesn't affect your current X session - you're already logged in!)
This is sample output - yours may be different.
2

touch /etc/nologin

udim · 2009-04-29 19:43:14 4
Nice info browser

pinfo package provide a nice info alternative based on ncurses.
This is sample output - yours may be different.
9

pinfo

servermanaged · 2009-04-29 19:08:37 10
Apache memory usage
This is sample output - yours may be different.
4

ps auxf | grep httpd | grep -v grep | grep -v defunct | awk '{sum=sum+$6}; END {print sum/1024}'

empulse · 2009-04-29 17:43:52 32
Display time of accounts connection on a system

Works on CentOS ad OpenBSD too, display time of accounts connection on a system, -p option print individual user's statistics. Show Sample Output
This is sample output - yours may be different.
```
# ac -p
        nastic                               1.17
        root                                22.67
        total                               23.83
```
2

ac -p

servermanaged · 2009-04-29 16:24:07 230
One liner gdb attach to Acrobat
This is sample output - yours may be different.
0

(acroread &);sleep 2;gdb /opt/Adobe/Reader8/Reader/intellinux/bin/acroread `pidof ld-linux.so.2`

rhythmx · 2009-04-29 16:23:48 11
Get file access control list
This is sample output - yours may be different.
3

getfacl /mydir

servermanaged · 2009-04-29 11:57:14 7
Convert ip address in hexadecimal

Show Sample Output
This is sample output - yours may be different.
```
#  gethostip 208.69.34.230 -x
D04522E6
```
0

gethostip 208.69.34.230 -x

servermanaged · 2009-04-29 11:46:30 3
Change Gnome wallpaper

You can use this in a script which rotates wallpapers from a directory at each login.
This is sample output - yours may be different.
2

gconftool-2 -t string -s /desktop/gnome/background/picture_filename <path_to_image>

o6291408 · 2009-04-29 11:19:29 9
Split lossless audio (ape, flac, wav, wv) by cue file

Do you have an entire album in a unique file and want to split it in individual tracks? If you also have the cue file you can do it! Packages for Debian-based systems users: * cuetools shntool * FLAC (.flac): flac * WavPack (.wv): wavpack * Monkey's Audio (.ape): libmac2 monkeys-audio (deb http://www.debian-multimedia.org sid main) NOTE: "sid" packages are unstable, but I didn't have problems with them. If you prefer, use the "stable" version repository. To transfer the tags, you can use this (works with .flac, .ogg and .mp3): cuetag sample.cue split-track*.flac Show Sample Output
This is sample output - yours may be different.
```
cuebreakpoints sample.cue | shnsplit -o flac sample.ape
Splitting [sample.ape] (76:02.37) --> [split-track01.flac] (7:37.17) : 100% OK
Splitting [sample.ape] (76:02.37) --> [split-track02.flac] (4:33.50) : 100% OK
Splitting [sample.ape] (76:02.37) --> [split-track03.flac] (4:18.18) : 100% OK
Splitting [sample.ape] (76:02.37) --> [split-track04.flac] (4:31.17) : 100% OK
Splitting [sample.ape] (76:02.37) --> [split-track05.flac] (3:47.05) : 100% OK
...
```
5

cuebreakpoints <cue file> | shnsplit -o <lossless audio type> <audio file>

o6291408 · 2009-04-29 10:42:57 4
Send pop-up notifications on Gnome

The title is optional. Options: -t: expire time in milliseconds. -u: urgency (low, normal, critical). -i: icon path. On Debian-based systems you may need to install the 'libnotify-bin' package. Useful to advise when a wget download or a simulation ends. Example: wget URL ; notify-send "Done"
This is sample output - yours may be different.
46

notify-send ["<title>"] "<body>"

o6291408 · 2009-04-29 10:05:20 21
Interactively build regular expressions

txt2regex can be interactive or noninteractive and generates regular expressions for a variety of dialects based on user input. In interactive mode, the regex string builds as you select menu options. The sample output here is from noninteractive mode, try running it standalone and see for yourself. It's written in bash and is available as the 'txt2regex' package at least under debian/ubuntu. Show Sample Output
This is sample output - yours may be different.
```
$ txt2regex --make date --prog vi,perl

### date LEVEL 1: mm/dd/yyyy: matches from 00/00/0000 to 99/99/9999

 RegEx vi  : [0-9]\{2\}/[0-9]\{2\}/[0-9]\{4\}
 RegEx perl: [0-9]{2}/[0-9]{2}/[0-9]{4}
```
8

txt2regex

bwoodacre · 2009-04-29 04:00:22 9
Quickly determine lines in terminal

You've opened a terminal window and you've connected off to a remote host that didn't pick up your terminal size, and all your curses and paging apps are screwed up as a result. You need to quickly determine how many lines are in your current terminal view (to feed into "stty rows X"). Show Sample Output
This is sample output - yours may be different.
```
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
```
-2

_llines=100; while [ $_llines -gt 1 ]; do echo $_llines; _llines=$(($_llines-1)); done

romulusnr · 2009-04-29 00:19:45 7
Convert camelCase to underscores (camel_case)

Useful for switching over someone else's coding style who uses camelCase notation to your style using all lowercase with underscores. Show Sample Output
This is sample output - yours may be different.
```
$ cat file.txt
camelCase
$ sed -r 's/([a-z]+)([A-Z][a-z]+)/\1_\l\2/g' file.txt
camel_case
```
11

sed -r 's/([a-z]+)([A-Z][a-z]+)/\1_\l\2/g' file.txt

atoponce · 2009-04-28 22:44:45 15
Clone /

Clone linux installation.
This is sample output - yours may be different.
1

find . -path ./mnt -prune -o -path ./lost+found -prune -o -path ./sys -prune -o -path ./proc -prune -o -print | cpio -pumd /destination && mkdir /destination/mnt/ && mkdir /destination/proc && mkdir /destination/sys

nutria · 2009-04-28 22:14:45 7
Clone current directory into /destination verbosely

Copy every file from current directory to destination preserving modification time.
This is sample output - yours may be different.
3

find . | cpio -pumdv /destination

nutria · 2009-04-28 22:08:30 8
Set your profile so that you resume or start a screen session on login

From screen's manpage: "Attach here and now. In detail this means: If a session is running, then reattach. If necessary detach and logout remotely first. If it was not running create it and notify the user. This is the author's favorite." Toss this in your ~/.bash_profile so that you never have that "oh crap" moment where you wanted to run something in screen and didn't.
This is sample output - yours may be different.
11

echo "screen -DR" >> ~/.bash_profile

sud0er · 2009-04-28 20:45:37 5
Securely destroy data (including whole hard disks)

GNU shred is provided by the coreutils package on most Linux distribution (meaning, you probably have it installed already), and is capable of wiping a device to DoD standards. You can give shred any file to destroy, be it your shell history or a block device file (/dev/hdX, for IDE hard drive X, for example). Shred will overwrite the target 25 times by default, but 3 is enough to prevent most recovery, and 7 passes is enough for the US Department of Defense. Use the -n flag to specify the number of passes, and man shred for even more secure erasing fun. Note that shredding your shell history may not be terribly effective on devices with journaling filesystems, RAID copies or snapshot copies, but if you're wiping a single disk, none of that is a concern. Also, it takes quite a while :)
This is sample output - yours may be different.
5

shred targetfile

sud0er · 2009-04-28 19:57:43 9
Enable Hibernate in OS X
This is sample output - yours may be different.
-3

sudo pmset -a hibernatemode 1

therod · 2009-04-28 19:53:57 5
Install an mpkg from the command line on OSX

Installing most OSX apps is just a matter of dropping it in /Applications, either GUI-wise or with cp -r. However, many packages are distributed in "mpkg" format, and those have to be installed with an installer. If you don't want to go to the trouble of firing up VNC to install an mpkg, you can use the "installer" command. This will install an application from a .mpkg it to /Applications system-wide. To install a program for just one user, replace "-target /" with "-target username".
This is sample output - yours may be different.
4

sudo installer -pkg /Volumes/someapp/someapp.mpkg -target /

sud0er · 2009-04-28 19:43:56 53
Mount a disk image (dmg) file in Mac OSX

To unmount, replace "attach" with "eject"
This is sample output - yours may be different.
5

hdiutil attach somefile.dmg

sud0er · 2009-04-28 19:41:42 5
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Catch a proccess from a user and strace it.

It sits there in a loop waiting for a proccess from that user to spawn. When it does it will attach strace to it

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.

Find the package that installed a command

mplayer webcam window for screencasts

When recording screencast some people like to have the image from their webcam, so the can show something, that can't be seen on the desktop. So starting mplayer with these parameters you will have a window with no frames, borders whatsoever, and selecting the window a hitting the "F" key you will bring it in fullscreen. if you want to position the frame somewhere else, you could play with the --geomeptry option where 100%:100% mean bottom right corner. The HEIGHT and WIDTH can't be changed as you like, since the most webcams support specified dimensions, so you would have to play with it to see what is supported

Remove lines that contain a specific pattern($1) from file($2).

The -i option in sed allows in-place editing of the input file. Replace myexpression with any regular expression. /expr/d syntax means if the expression matches then delete the line. You can reverse the functionality to keep matching lines only by using: $ sed -i -n '/myexpression/p' /path/to/file.txt

Rename files in batch

clone an USB stick using dd + see its process

The following command will clone usb stick inside /dev/sdc to /dev/sdd Double check you got the correct usb sticks (origional-clone)with fdisk -l.

One line Perl Script to determine the largest file sizes on a Linux Server

This one line Perl script will display the smallest to the largest files sizes in all directories on a server.

Convert seconds to [DD:][HH:]MM:SS

Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Perl one liner for epoch time conversion

Converts Unix epoch time to localtime. Useful for any logs that only display epoch time.

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