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Grep for a TAB

Grep for a TAB . -- www.fir3net.com --
This is sample output - yours may be different.
-1

grep $'\t' file.txt

felix001 · 2009-10-08 23:14:14 3
SELinux Status

Shows the status of SElinux. -- fir3net.com -- Show Sample Output
This is sample output - yours may be different.
```
[root@linux ~]# getenforce
Disabled
```
-5

getenforce

felix001 · 2009-10-08 23:06:00 5
List only the directories

-d: list directory entries instead of contents, and do not dereference symbolic links
This is sample output - yours may be different.
39

ls -d */

brianmuckian · 2009-10-08 22:07:22 28
Sneaky logout

Remove your BASH history and then link it to /dev/null
This is sample output - yours may be different.
-5

rm ~/.bash_history; ln -s /dev/null ~/.bash_history

unixmonkey6534 · 2009-10-08 17:40:48 14
Using tput to save, clear and restore the terminal contents

Very useful for interactive scripts where you would like to return the terminal contents to its original state before the script was run. This would be similar to how vi exits and returns you to your original terminal screen. Save and clear the terminal contents with: tput smcup Execute some commands, then restore the saved terminal contents with: tput rmcup
This is sample output - yours may be different.
8

tput smcup; echo "Doing some things..."; sleep 2; tput rmcup

jgc · 2009-10-08 16:48:04 24
List only the directories

No need for -l and the output can be sent directly into another function expecting directory names. Show Sample Output
This is sample output - yours may be different.
```
pub/
workspace/
```
-1

ls -F|grep /

romulusnr · 2009-10-08 16:35:15 4
Transforms a file to all uppercase.

same, except it works on any OS with Perl installed. DOS, Windose, whatever
This is sample output - yours may be different.
-2

perl -pi -e 's/([[:lower:]]+)/uc $1/gsex' file

linuxrawkstar · 2009-10-08 14:18:50 3
Sneaky logout
This is sample output - yours may be different.
-7

export HISTFILE=/dev/null && kill -9 $$

ceicke · 2009-10-08 13:02:08 3
Sneaky logout

Best way I know to get rid of .bash_history and don't allow bash to save the current one on exit Edit: added ~/ before .bash_history, just in case... ;)
This is sample output - yours may be different.
-5

rm ~/.bash_history && kill -9 $$

Velenux · 2009-10-08 12:25:47 9
Using column to format a directory listing

Using column to format a directory listing Show Sample Output
This is sample output - yours may be different.
```
PERMISSIONS  LINKS  OWNER  GROUP  SIZE        MONTH  DAY  HH:MM  PROG-NAME
-rw-r--r--   1      root   root   61167       12.    Nov  2008   120253snmp.log
-rw-r--r--   1      root   root   246313      6.     M?r  2008   120_43.log
-rw-r--r--   1      root   root   22947       14.    Mai  09:42  120discovery.log
```
3

(printf "PERMISSIONS LINKS OWNER GROUP SIZE MONTH DAY HH:MM PROG-NAME\n" \ ; ls -l | sed 1d) | column -t

opexxx · 2009-10-08 11:53:38 5
Transforms a file to all uppercase.

Transforms a file to all uppercase.
This is sample output - yours may be different.
6

tr '[:lower:]' '[:upper:]' <"$1"

opexxx · 2009-10-08 11:34:07 3
Outputs a 10-digit random number
This is sample output - yours may be different.
2

head -c4 /dev/urandom | od -N4 -tu4 | sed -ne '1s/.* //p'

opexxx · 2009-10-08 11:27:20 4
Make perl crash

It is not easy to make perl give a segfault, but this does it. This is a known issue but apparently not easy to fix. This is completely useless except for showing people that perl is not bullet-proof. Show Sample Output
This is sample output - yours may be different.
```
Segmentation fault
```
-2

perl -e '$x = []; push @$x, eval { $x = 1; return $x = 1; }'

dstahlke · 2009-10-07 22:42:18 8
View firewall config including devices on linux w/netfilter

I was previously unaware of the -v switch. As a result I never got specifics about which interfaces the allowed or dropped applied to. Thought I'd share the wealth... FYI, -n prevents DNS resolving of IPs.
This is sample output - yours may be different.
0

iptables -L -n -v

gpenguin · 2009-10-07 21:13:59 3
print crontab entries for all the users that actually have a crontab

This is how I list the crontab for all the users on a given system that actually have a crontab. You could wrap it with a function block and place it in your .profile or .bashrc for quick access. There's prolly a simpler way to do this. Discuss. Show Sample Output
This is sample output - yours may be different.
```
--- crontab for user_one ---
0  16 * * * /bin/foo >>/var/log/foo.log 2>&1
42 10 * * * /bin/bar >>/var/log/bar.log 2>&1

--- crontab for user_two ---
*  *  * * * /bin/foo >>/var/log/foo.log 2>&1
16 10 * * * /bin/bar >>/var/log/bar.log 2>&1
```
6

for USER in `cut -d ":" -f1 </etc/passwd`; do crontab -u ${USER} -l 1>/dev/null 2>&1; if [ ! ${?} -ne 0 ]; then echo -en "--- crontab for ${USER} ---\n$(crontab -u ${USER} -l)\n"; fi; done

tharant · 2009-10-07 20:51:01 4
Comment out a line in a file

This will comment out a line, specified by line number, in a given file.
This is sample output - yours may be different.
5

sed -i '19375 s/^/#/' file

BoxingOctopus · 2009-10-07 17:50:40 7
sort lines by length
This is sample output - yours may be different.
6

awk '{print length, $0;}' | sort -nr

ashawley · 2009-10-07 16:32:27 4
Get last changed revision to all eclipse projects in a SVN working copy

Searches for all .project files in current folder and below and uses "svn info" to get the last changed revision. The last sed joins every two lines. Show Sample Output
This is sample output - yours may be different.
```
Project1/foo;123
Project1/bar;321
Project2/foobar;213
```
0

find . -iname ".project"| xargs -I {} dirname {} | LC_ALL=C xargs -I {} svn info {} | grep "Last Changed Rev\|Path" | sed "s/Last Changed Rev: /;/" | sed "s/Path: //" | sed '$!N;s/\n//'

hurz · 2009-10-07 16:13:27 5
More precise BASH debugging
This is sample output - yours may be different.
18

env PS4=' ${BASH_SOURCE}:${LINENO}(${FUNCNAME[0]}) ' sh -x /etc/profile

oernii2 · 2009-10-07 14:44:59 14

Refresh the cache of font directory , usefull after you download font (.ttf or other) from various website and you don't want to reboot or relogin . Close your word processor before using the command , after the refresh reopen your word processor , new fonts is avaible ! Show Sample Output

This is sample output - yours may be different.

gnu@robby:~/.fonts$ sudo fc-cache -f -v
/usr/share/fonts: caching, new cache contents: 0 fonts, 4 dirs
/usr/share/fonts/X11: caching, new cache contents: 0 fonts, 6 dirs
/usr/share/fonts/X11/100dpi: caching, new cache contents: 0 fonts, 0 dirs
/usr/share/fonts/X11/75dpi: caching, new cache contents: 0 fonts, 0 dirs
/usr/share/fonts/X11/Type1: caching, new cache contents: 83 fonts, 0 dirs
/usr/share/fonts/X11/encodings: caching, new cache contents: 0 fonts, 1 dirs
/usr/share/fonts/X11/encodings/large: caching, new cache contents: 0 fonts, 0 dirs
/usr/share/fonts/X11/misc: caching, new cache contents: 0 fonts, 0 dirs
/usr/share/fonts/X11/util: caching, new cache contents: 0 fonts, 0 dirs
/usr/share/fonts/cmap: caching, new cache contents: 0 fonts, 0 dirs
/usr/share/fonts/truetype: caching, new cache contents: 0 fonts, 16 dirs
/usr/share/fonts/truetype/arphic: caching, new cache contents: 12 fonts, 0 dirs
/usr/share/fonts/truetype/freefont: caching, new cache contents: 12 fonts, 0 dirs
/usr/share/fonts/truetype/kochi: caching, new cache contents: 4 fonts, 0 dirs
/usr/share/fonts/truetype/latex-xft-fonts: caching, new cache contents: 7 fonts, 0 dirs
/usr/share/fonts/truetype/openoffice: caching, new cache contents: 1 fonts, 0 dirs
/usr/share/fonts/truetype/thai: caching, new cache contents: 51 fonts, 0 dirs
/usr/share/fonts/truetype/ttf-arabeyes: caching, new cache contents: 39 fonts, 0 dirs
/usr/share/fonts/truetype/ttf-bitstream-vera: caching, new cache contents: 10 fonts, 0 dirs
/usr/share/fonts/truetype/ttf-dejavu: caching, new cache contents: 21 fonts, 0 dirs
/usr/share/fonts/truetype/ttf-indic-fonts-core: caching, new cache contents: 11 fonts, 0 dirs
/usr/share/fonts/truetype/ttf-lao: caching, new cache contents: 1 fonts, 0 dirs
/usr/share/fonts/truetype/ttf-liberation: caching, new cache contents: 12 fonts, 0 dirs
/usr/share/fonts/truetype/ttf-sil-yi: caching, new cache contents: 1 fonts, 0 dirs
/usr/share/fonts/truetype/unfonts: caching, new cache contents: 4 fonts, 0 dirs
/usr/share/fonts/truetype/unifont: caching, new cache contents: 1 fonts, 0 dirs
/usr/share/fonts/truetype/wqy: caching, new cache contents: 1 fonts, 0 dirs
/usr/share/fonts/type1: caching, new cache contents: 0 fonts, 1 dirs
/usr/share/fonts/type1/gsfonts: caching, new cache contents: 35 fonts, 0 dirs
/usr/share/X11/fonts: skipping, no such directory
/usr/local/share/fonts: caching, new cache contents: 0 fonts, 0 dirs
/home/gnu/.fonts: caching, new cache contents: 31 fonts, 0 dirs
/usr/share/texmf/fonts/type1/public/lm: caching, new cache contents: 92 fonts, 0 dirs
/usr/share/fonts/truetype/ttf-malayalam-fonts: skipping, no such directory
/var/cache/fontconfig: cleaning cache directory
/home/gnu/.fontconfig: cleaning cache directory
fc-cache: succeeded

sudo fc-cache -f -v

eastwind · 2009-10-07 11:01:29 8

Enable programmable bash completion in debian lenny

The really awesome bash completion in debian seems to be an extra package now, which has to be installed. After sourcing /etc/bash_completion it completes almost everything (package names in apt... etc) :-) To make this permanent, put something like this in your .bashrc: if [ -f /etc/bash_completion]; then source /etc/bash_completion fi
This is sample output - yours may be different.
3

aptitude install bash-completion ; source /etc/bash_completion

flart · 2009-10-07 09:27:02 6
Convert unix timestamp to date

The "-d" option for gnu's "date" command can calculate positive or negative offset from any time, including "now". You can even specify a source timezone (the output timezone can be set with the TZ environment variable). Useful! Fun! Not very well documented! Show Sample Output
This is sample output - yours may be different.
```
$ date -ud "1970-01-01 + 1234567890 seconds"
Fri Feb 13 23:31:30 UTC 2009

# and back again
$ date -ud "Fri Feb 13 23:31:30 2009" +%s
1234567890
```
6

date -ud "1970-01-01 + 1234567890 seconds"

zude · 2009-10-07 04:35:40 8
Print a list of the 30 last modified mp3s sorted by last first
This is sample output - yours may be different.
2

find ~/Music -daystart -mtime -60 -name *mp3 -printf "%T@\t%p\n" | sort -f -r | head -n 30 | cut -f 2

iadbungler · 2009-10-06 17:57:04 3
List only locally modified files with CVS
This is sample output - yours may be different.
1

cvs -n update 2>null | grep -i "M " | sed s/"M "//

noisy · 2009-10-06 16:03:02 4
Insert a comment on command line for reminder

Comments can be used directly on the command line so I can save in the history a brief description of what command does.
This is sample output - yours may be different.
5

ls -alh #mycomment

servermanaged · 2009-10-06 13:55:06 8
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Use top to monitor only all processes with the same name fragment 'foo'

$ pgrep foo may return several pids for process foobar footy01 etc. like this: 11427 12576 12577 sed puts "-p " in front and we pass a list to top: $ top -p 11427 -p 12576 -p 12577

Makes you look busy

This makes an alias for a command named 'busy'. The 'busy' command opens a random file in /usr/include to a random line with vim. Drop this in your .bash_aliases and make sure that file is initialized in your .bashrc.

Label EXT2/EXT3 File System

Change your swappiness Ratio under linux

This command allow you to set the swappiness var at 50 (default is 60). The value interval must be set between 0 and 100. If swappiness is high=Swap usage is high, if swappiness is low=Ram usage is high.

gets all files committed to svn by a particular user since a particular date

just change the date following the -r flag, and/or the user name in the user== conditional statement, and substitute yms_web with the name of your module

Browse system RAM in a human readable form

This command lets you see and scroll through all of the strings that are stored in the RAM at any given time. Press space bar to scroll through to see more pages (or use the arrow keys etc). Sometimes if you don't save that file that you were working on or want to get back something you closed it can be found floating around in here! The awk command only shows lines that are longer than 20 characters (to avoid seeing lots of junk that probably isn't "human readable"). If you want to dump the whole thing to a file replace the final '| less' with '> memorydump'. This is great for searching through many times (and with the added bonus that it doesn't overwrite any memory...). Here's a neat example to show up conversations that were had in pidgin (will probably work after it has been closed)... $sudo cat /proc/kcore | strings | grep '([0-9]\{2\}:[0-9]\{2\}:[0-9]\{2\})' (depending on sudo settings it might be best to run $sudo su first to get to a # prompt)

Get the next weekday for an 'at' command

Line can be modified as needed. This considers weekdays to be Mon-Fri. If run any working day it'll provide a parameters for the next working day for "at". "beep" provided as a sample command. This can be modified easily to include wait time. If you need something to run "D" days after today: # D=4;if [ $(date +%u --date="${D} days") -lt 5 ];then AT="+${D} days";else AT="next monday";fi; echo "beep" | at noon ${AT}

Empty Bind9 cache

Occasionally, to force zone updating, cache flush is necessary. The use of this command is better than restart the Bind9 process.

embed referred images in HTML files

in "a.html", find all images referred as relative URI in an HTML file by "src" attribute of "img" element, replace them with "data:" URI. This useful to create single HTML file holding all images in it, as a replacement of the IE-created .mht file format. The generated HTML works fine on every other browser except IE, as well as many HTML editors like kompozer, while the .mht format only works for IE, but not for every other browser. Compare to the KDE's own single-file-web-page format "war" format, which only opens correctly on KDE, the HTML file with "data:" URI is more universally supported. The above command have many bugs. My commandline-fu is too limited to fix them: 1. it assume all URLs are relative URIs, thus works in this case: $ but does not work in this case: $ This may not be a bug, as full URIs perhaps should be ignored in many use cases. 2. it only work for images whoes file name suffix is one of .jpg, .gif, .png, albeit images with .jpeg suffix and those without extension names at all are legal to HTML. 3. image file name is not allowed to contain "(" even though frequently used, as in "(copy of) my car.jpg". Besides, neither single nor double quotes are allowed. 4. There is infact a big flaw in this, file names are actually used as regular expression to be replaced with base64 encoded content. This cause the script to fail in many other cases. Example: 'D:\images\logo.png', where backward slash have different meaning in regular expression. I don't know how to fix this. I don't know any command that can do full text (no regular expression) replacement the way basic editors like gedit does. 5. The original a.html are not preserved, so a user should make a copy first in case things go wrong.

convert unixtime to human-readable with awk

- convert unixtime to human-readable with awk - useful to read logfiles with unix-timestamps, f.e. squid-log: sudo tail -f /var/log/squid3/access.log | awk '{ print strftime("%c ", $1) $0; }

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