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Find removed files still in use via /proc

Oracle DBA remove some logfiles which are still open by the database and he is complaining the space has not been reclaimed? Use the above command to find out what PID needs to be stopped. Or alternatively recover the file via: cp /proc/pid/fd/filehandle /new/file.txt Show Sample Output

find -L /proc/*/fd -links 0 2>/dev/null

res0nat0r · 2009-06-26 18:42:51 12

Show your account and windows policy settings with Results of Policy msc.

Type this into windows via run and it will display to you your complete policy for windows. This includes group policy, security policy and your active directory account (min password etc).... www.fir3net.com
This is sample output - yours may be different.
4

rsop.msc

felix001 · 2009-06-26 11:19:50 13

Monitor RX/TX packets and any subsquent errors

www.fir3net.com Show Sample Output

watch 'netstat -aniv'

felix001 · 2009-06-26 11:16:42 8

Most simple way to get a list of open ports
This is sample output - yours may be different.
3

netstat -lnp

unixmonkey4415 · 2009-06-26 08:33:03 8
Check processes runed not by you
This is sample output - yours may be different.
-4

ps aux | grep -v `whoami`

unixmonkey4415 · 2009-06-26 08:28:06 8
Merge several pdf files into a single file
This is sample output - yours may be different.
3

pdftk $* cat output $merged.pdf

svg · 2009-06-26 07:36:02 11
bash or tcsh redirect both to stdout and to a file

When plumbers use pipes, they sometimes need a T-joint. The Unix equivalent to this is 'tee'. The -a flag tells 'tee' to append to the file, rather than clobbering it. Tested on bash and tcsh. Show Sample Output
This is sample output - yours may be different.
```
$ echo "Hello World." | tee -a hello.txt
Hello World.
$ cat hello.txt
Hello World.
```
1

echo "Hello World." | tee -a hello.txt

thebillywayne · 2009-06-26 00:55:59 9
Print multiline text starting and ending at specific regexps with perl

Using perl, here, we grep the man page of fetchmail to find the paragraph starting with '-k | --keep' and ending before the paragraph starting with '-K | --nokeep' Show Sample Output
This is sample output - yours may be different.
```
-k | --keep
              (Keyword:  keep)  Keep  retrieved messages on the remote mailserver.  Normally, messages are deleted from the folder on the mailserver after they have been retrieved.  Specifying
              the keep option causes retrieved messages to remain in your folder on the mailserver.  This option does not work with ETRN or ODMR. If used with POP3, it is recommended  to  also
              specify the --uidl option or uidl keyword.

       
```
0

man fetchmail | perl -ne 'undef $/; print $1 if m/^.*?(-k \| --keep.*)-K \| --nokeep.*$/smg'

unixmonkey4437 · 2009-06-25 23:51:35 10
Set an alarm to wake up [2]

Set an alarm to starts in specific time. Show Sample Output
This is sample output - yours may be different.
```
For instance:
echo "aplay /media/dados/audio/geral/Yahoo.wav" | at 16:28
```
8

echo "aplay path/to/song" |at [time]

brausen · 2009-06-25 19:33:37 12
Set an alarm to wake up

Sleep 5h and plays the song as a wake up alarm
This is sample output - yours may be different.
3

sleep 5h && rhythmbox path/to/song

becomingGuru · 2009-06-25 19:15:19 12
Merge several pdf files into a single file

merge a.pdf b.pdf and c.pdf and create ./out.pdf
This is sample output - yours may be different.
5

gs -q -sPAPERSIZE=a4 -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=out.pdf a.pdf b.pdf c.pdf

becomingGuru · 2009-06-25 19:04:28 14
Get a shell with a not available account

Show Sample Output
This is sample output - yours may be different.
```
[root@XXX ~]# su - nobody
This account is currently not available.
[root@XXX ~]# su - nobody -s /bin/sh -c "/bin/sh"
sh-3.2$ id
uid=99(nobody) gid=99(nobody) grupos=99(nobody) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
```
3

su - <user> -s /bin/sh -c "/bin/sh"

nablas · 2009-06-25 15:36:04 12
Scan Network for Rogue APs.

I've used this scan to sucessfully find many rogue APs on a very, very large network. Show Sample Output
This is sample output - yours may be different.
```
Outputs data in greppable format, plain text and XML. The XML output has an associated XSL stylesheet, which allows you to open the data in a browser. 
```
7

nmap -A -p1-85,113,443,8080-8100 -T4 --min-hostgroup 50 --max-rtt-timeout 2000 --initial-rtt-timeout 300 --max-retries 3 --host-timeout 20m --max-scan-delay 1000 -oA wapscan 10.0.0.0/8

merkmerc · 2009-06-25 14:12:26 8
Open a Remote Desktop (RDP) session with a custom resolution.

Using a widescreen monitor, I often get annoyed that the RDP window is too high, or too narrow for what I want to display. In this example, I'm on a 1680 x 1050 display.
This is sample output - yours may be different.
1

mstsc /w:1500 /h:900 /v:www.example.com

merkmerc · 2009-06-25 14:01:42 9

get linkspeed, ip-adress, mac-address and processor type from osx

get desired info from machine and pipe it txt file. Show Sample Output

-2

echo "-------------" >> nicinfo.txt; echo "computer name x" >> nicinfo.txt; ifconfig | grep status >> nicinfo.txt; ifconfig | grep inet >> nicinfo.txt; ifconfig | grep ether >> nicinfo.txt; hostinfo | grep type >> nicinfo.txt;

miccaman · 2009-06-25 12:32:37 31

Disable graphical login on Solaris

With a full installation of Solaris 10, the graphical login and desktop will start by default. This command will disable that feature. To enable it again use: /usr/dt/bin/dtconfig -e Show Sample Output
This is sample output - yours may be different.
```
done 
desktop auto-start disabled. 
```
1

/usr/dt/bin/dtconfig -d

thesuperjason · 2009-06-25 09:32:37 8
Adobe Updater Crashes on Mac OS X Fix

adobe updater keeps popping up. (normal update fails, probably due to insufficient rights) (src: http://aricsblog.blogspot.com/2007/12/adobe-updater-crashes-on-mac-os-x-and.html)
This is sample output - yours may be different.
-9

sudo /Applications/Utilities/Adobe\ Utilities.localized/Adobe\ Updater5/Adobe\ Updater.app/Contents/MacOS/Adobe\ Updater

miccaman · 2009-06-25 08:07:47 18
Search command history on bash

Very handy and time-saving. Do a 'ctrl+ r' on command prompt. You will see a "(reverse-i-search)`':" mark. Just type any sub-string of the command you want to search(provided you have used it sometime in the same session). Keep on searching by repeatedly pressing ctrl+r. Press enter once you get the desired command string. Show Sample Output
This is sample output - yours may be different.
```
blue] $
(reverse-i-search)`': ls

#Press enter to run the selected command.
```
9

ctrl + r

Bluehive · 2009-06-25 06:51:38 12
Update dyndns.org with your external IP.

This is great if you are behind a router that does not support dynamic dns updates! Example: AT&T u-verse gateway... Put this in a script and run it as a cron job.
This is sample output - yours may be different.
5

curl -v -k -u user:password "https://members.dyndns.org/nic/update?hostname=<your_domain_name_here>&myip=$(curl -s http://checkip.dyndns.org | sed 's/[a-zA-Z<>/ :]//g')&wildcard=NOCHG&mx=NOCHG&backmx=NOCHG"

din7 · 2009-06-24 17:00:15 15
Sort a list of numbers on on line, separated by spaces.

You can replace "sort -nu" with "sort -u" for a word list sorted or "sort -R" for a random-sorted line (edit: corrected) Show Sample Output
This is sample output - yours may be different.
```
$ echo "4 2  3 5  2 52  11" | sed "s/$ \|$$/\n/g" | sort -nu | tr "\n" " "| sed -e "s/^ *//" -e "s/ $//"
2 3 4 5 11 52
```
-1

echo $numbers | sed "s/$ \|$$/\n/g" | sort -nu | tr "\n" " " | sed -e "s/^ *//" -e "s/ $//"

chickenzilla · 2009-06-24 15:12:17 7
Check if network cable is plugged in and working correctly

with 'mii-tool -w eth0' you can watch the interface for changes of the link status Show Sample Output
This is sample output - yours may be different.
```
eth0: negotiated 100baseTx-FD, link ok
```
6

mii-tool eth0

flart · 2009-06-24 08:43:55 11
String Capitalization

Helpful when we want to do mass file renaming(especially mp3s). Show Sample Output
This is sample output - yours may be different.
```
$ (STRING="COmManDLinEfU"; echo "${STRING}" | tr '[A-Z]' '[a-z]' | awk '{print toupper(substr($0,1,1))substr($0,2);}')
Commandlinefu
```
0

echo "${STRING}" | tr '[A-Z]' '[a-z]' | awk '{print toupper(substr($0,1,1))substr($0,2);}'

mohan43u · 2009-06-23 21:11:34 119
Size(k) of directories(Biggest first)

somewhat faster version to see the size of our directories. Size will be in Kilo Bytes. to view smallest first change '-k1nr' to '-k1n'.
This is sample output - yours may be different.
4

find . -depth -type d -exec du -s {} \; | sort -k1nr

mohan43u · 2009-06-23 20:52:35 11
Get the canonical, absolute path given a relative and/or noncanonical path

readlink -f accepts a relative, noncanonical path and emits the corresponding canonical, absolute path. Show Sample Output
This is sample output - yours may be different.
```
/tmp/foo/bar/baz/super/bon/bon/ahoy
```
11

readlink -f ../super/symlink_bon/ahoy

rbs · 2009-06-23 17:46:08 9
Migrate existing Ext3 filesystems to Ext4

Before doing this, back-up all data on any ext3 partitions that are to be converted to ext4. After running previous command you MUST run fsck, is needed to return the filesystem to a consistent state. fsck -pDf /dev/yourpartition Edit /etc/fstab and change the 'type' from ext3 to ext4 for any partitions that are converted to ext4.
This is sample output - yours may be different.
5

tune2fs -O extents,uninit_bg,dir_index /dev/yourpartition

starchox · 2009-06-23 17:42:01 14
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Remove color codes (special characters) with sed

Apache memory usage

print the name of each package APT knows [matching a prefix]

In this case, linux- is the prefix; simply running $apt-cache pkgnames would list every package APT knows about. The default APT config assumes -g, --generate; to use the cache as/is, you could similarly run: $apt-cache --no-generate pkgnames [prefix] Adding --all-names, like so: $apt-cache --no-generate --all-names pkgnames [prefix] would print all the packages APT knows about, using the cache as/is, including virtual packages and missing dependencies. This command was shamelessly stolen from the apt-cache(8) man-page.

Get contents from hosts, passwd, groups even if they're in DB/LDAP/other

getent allows to get the contents of several databases in their native file format even if they are not actually in /etc. For example, if you are using a LDAP or a DB to authenticate your users, you won't find their info by catting /etc/passwd, but "getent passwd" will concatenate /etc/passwd to the LDAP/DB.

Read and write to TCP or UDP sockets with common bash tools

Ever needed to test firewalls but didn't have netcat, telnet or even FTP? Enter /dev/tcp, your new best friend. /dev/tcp/(hostname)/(port) is a bash builtin that bash can use to open connections to TCP and UDP ports. This one-liner opens a connection on a port to a server and lets you read and write to it from the terminal. How it works: First, exec sets up a redirect for /dev/tcp/$server/$port to file descriptor 5. Then, as per some excellent feedback from @flatcap, we launch a redirect from file descriptor 5 to STDOUT and send that to the background (which is what causes the PID to be printed when the commands are run), and then redirect STDIN to file descriptor 5 with the second cat. Finally, when the second cat dies (the connection is closed), we clean up the file descriptor with 'exec 5>&-'. It can be used to test FTP, HTTP, NTP, or can connect to netcat listening on a port (makes for a simple chat client!) Replace /tcp/ with /udp/ to use UDP instead.

Display standard information about device

Queries the specified ethernet device for associated driver information

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.

vi a new file with execution mode

$ vix /tmp/script.sh Open a file directly with execution permission. Put the function in your .bashrc You can also put this in your vimrc: $ command XX w | set ar | silent exe "!chmod +x %" | redraw! and open a new file like this: $ vi +XX /tmp/script.sh

diff files while disregarding indentation and trailing white space

**NOTE** Tekhne's alternative is much more succinct and its output conforms to the files actual contents rather than with white space removed My command on the other hand uses bash process substitution (and "Minimal" Perl), instead of files, to first remove leading and trailing white space from lines, before diff'ing the streams. Very useful when differences in indentation, such as in programming source code files, may be irrelevant

Replace multiple file extensions with a single extension

The above is just a prove of concept based around the nested bash substitution. This could be useful in situations where you're in a directory with many filetypes but you only want to convert a few. $ for f in *.bmp *.jpg *.tga; do convert $f ${f%.*}.png; done or you can use ls | egrep to get more specific... but be warned, files with spaces will cause a ruckus with expansion but the bash for loop uses a space delimited list. $ for f in $(ls | egrep "bmp$|jpg$|tga$"); do convert $f ${f%.*}.png; done I'm guessing some people will still prefer doing it the sed way but I thought the concept of this one was pretty neat. It will help me remember bash substitutions a little better :-P

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