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Return IP Address

Tested on Solaris.
This is sample output - yours may be different.
-1

/usr/sbin/ifconfig -a|awk -F" " 'NR==4{print $2}'

elZaphod · 2009-12-04 18:41:29 4
Return threads count of a process

Source: http://superuser.com/questions/49408/how-do-i-monitor-or-view-the-thread-count-of-a-certain-process-on-aix Show Sample Output
This is sample output - yours may be different.
```
THCNT
   2
```
3

ps -o thcount -p <process id>

lukasz · 2009-12-04 14:39:53 4
View the newest xkcd comic.
This is sample output - yours may be different.
1

wget `lynx --dump http://xkcd.com/|grep png`

metalx1000 · 2009-12-03 23:10:22 3
Get the time from NIST.GOV

The format is JJJJJ YR-MO-DA HH:MM:SS TT L DUT1 msADV UTC(NIST) OTM and is explained more fully here: http://tf.nist.gov/service/acts.htm Show Sample Output
This is sample output - yours may be different.
```
cat </dev/tcp/time.nist.gov/13

55168 09-12-03 20:32:43 00 0 0 350.2 UTC(NIST) * 
```
8

cat </dev/tcp/time.nist.gov/13

drewk · 2009-12-03 21:40:14 11
Friendly command-not-found message.

This will give you a friendly warning if a command doesn't exists. Show Sample Output
This is sample output - yours may be different.
```
$ aptitypo
...
```
-1

command_not_found_handle() { echo 6661696c626f61742e2e2e0a | xxd -p -r; }

unixmonkey7301 · 2009-12-03 21:33:35 4
View the newest xkcd comic.

I wasn't sure how to display the image, so I thought I'd try xml for a different twist. Show Sample Output
This is sample output - yours may be different.
```
<?xml version="1.0"?>
<xkcd>
<item>
<title>Spinal Tap Amps</title>
<comment>Wow, that's less than $200 per ... uh ... that's a good deal!</comment>
<image>http://imgs.xkcd.com/comics/spinal_tap_amps.png</image>
</item>
</xkcd>
```
0

curl -s 'xkcd.com' | awk -F\" '/^<img/{printf("<?xml version=\"1.0\"?>\n<xkcd>\n<item>\n <title>%s</title>\n <comment>%s</comment>\n <image>%s</image>\n</item>\n</xkcd>\n", $6, $4, $2)}'

putnamhill · 2009-12-03 19:49:37 3
View the newest xkcd comic.

Same thing just a different way to get there. You will need lynx
This is sample output - yours may be different.
-1

lynx --dump --source http://www.xkcd.com | grep `lynx --dump http://www.xkcd.com | egrep '(png|jpg)'` | grep title | cut -d = -f2,3 | cut -d '"' -f2,4 | sed -e 's/"/|/g' | awk -F"|" ' { system("display " $1);system("echo "$2); } '

solarislackware · 2009-12-03 18:53:57 3
Watch those evil Red Hat states code D Uninterruptible sleep (usually IO).

On my cluster a D in the states column means it is time to reboot the server.
This is sample output - yours may be different.
0

watch -n 1 "ps aux | sed -n 's/ D /&/p'"

lunarblu · 2009-12-03 18:22:44 3
Fill up disk space (for testing)

For disk space constraint testing. Leaves a little space available for creating temp files, etc. Easily free up the used disk space again by deleting the dummy00 file. Can tailor the testing by building smaller 'blocks' to suit the needs of the testing. WARNING: do not do this to the '/' (root) filesystem unless you know what you are doing... on some systems it could crash the OS.
This is sample output - yours may be different.
-3

dd if=/dev/zero of=/fs/to/fill/dummy00 bs=8192 count=$(df --block-size=8192 / | awk 'NR!=1 {print $4-100}')

arcege · 2009-12-03 15:20:18 5
Mirror the NASA Astronomy Picture of the Day Archive

Mirror the entire NASA Astronomy Picture of the Day archive, all the way from 1995. The archive is close to 2.5 GB, with lots of files, so give it some time. The logs can be redirected to a file using '-o somefile'. You might also want to try '-nH' and the '--cut-dirs' options
This is sample output - yours may be different.
3

wget -t inf -k -r -l 3 -p -m http://apod.nasa.gov/apod/archivepix.html

ninadsp · 2009-12-03 10:27:57 7
Strace all signals processes based on a name ( The processes already started... ) with bash built-in

Especially for sysadmins when they don't want to waste time to add -p flag on the N processes of a processname. In the old school, you did ; pgrep processname and typing strace -f -p 456 -p 678 -p 974... You can add -f argument to the function. That way, the function will deal with pgrep to match the command-line. Example : processname -f jrockit
This is sample output - yours may be different.
3

straceprocessname(){ x=( $(pgrep "$@") ); [[ ${x[@]} ]] || return 1; strace -vf ${x[@]/#/-p }; }

sputnick · 2009-12-03 00:04:39 8
search for a pattern (regex) in all text files (ignoring binary files) in a directory tree
This is sample output - yours may be different.
-2

egrep -i "somepattern" `find . -type f -print`

dudleyperkins · 2009-12-02 16:00:46 5
generate random password

for Mac OS X Show Sample Output
This is sample output - yours may be different.
```
rUYIwxq4
```
8

openssl rand -base64 6

gikku · 2009-12-02 10:10:58 12
ruby one-liner to get the current week number
This is sample output - yours may be different.
3

ruby -rdate -e 'p DateTime.now.cweek'

Tekhne · 2009-12-02 02:33:51 33
yesterday
This is sample output - yours may be different.
-4

perl -lne 'use POSIX; print strftime("%Y-%m-%d", localtime(time() - 86400));'

unixmonkey7263 · 2009-12-01 22:31:34 14
perl one-liner to get the current week number

Not perl but shorter.
This is sample output - yours may be different.
20

date +%V

putnamhill · 2009-12-01 21:40:56 9
Mail text file (/tmp/scream-dump) contents from linux box with subject(scream-dump)
This is sample output - yours may be different.
-1

mail -s scream-dump user@example.com < /tmp/scream-dump

imsaar · 2009-12-01 21:04:22 3
Convert encoding of given files from one encoding to another
This is sample output - yours may be different.
4

iconv -f utf8 -t utf16 /path/to/file

imsaar · 2009-12-01 21:02:58 3
find all writable (by user) files in a directory tree (use 4 for readable, 1 for executable)
This is sample output - yours may be different.
1

find . -type f -perm +200 -print

imsaar · 2009-12-01 21:01:46 3
ruby one-liner to get the current week number
This is sample output - yours may be different.
-1

ruby -e 'require "date"; puts DateTime.now.cweek'

imsaar · 2009-12-01 20:59:18 3
lists contents of a tar file
This is sample output - yours may be different.
0

tar -tf /path/to/file.tar

imsaar · 2009-12-01 20:58:07 4
perl one-liner to get the current week number
This is sample output - yours may be different.
-3

perl -e 'use Date::Calc qw(Today Week_Number); $weekn = Week_Number(Today); print "$weekn\n"'

imsaar · 2009-12-01 20:56:13 3
search for a pattern (regex) in all text files (ignoring binary files) in a directory tree
This is sample output - yours may be different.
-1

find . -type f | perl -lne 'print if -T;' | xargs egrep "somepattern"

unixmonkey7263 · 2009-12-01 19:12:03 6
Find dead symbolic links
This is sample output - yours may be different.
1

find . -type l | perl -lne 'print if ! -e'

unixmonkey7263 · 2009-12-01 19:08:45 5
Drop all tables from a database, without deleting it
This is sample output - yours may be different.
1

MYSQL="mysql -h HOST -u USERNAME -pPASSWORD -D DB_NAME" ; $MYSQL -BNe "show tables" | awk '{print "set foreign_key_checks=0; drop table `" $1 "`;"}' | $MYSQL unset MYSQL

gadget00 · 2009-12-01 17:42:38 7
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Quickly generate an MD5 hash for a text string using OpenSSL

hanukkah colored bash prompt

blue and yellow colored bash prompt for a Hanukkah celebration on your box

Bitcoin Brainwallet Private Key Calculator

A bitcoin "brainwallet" is a secret passphrase you carry in the "wallet" of your brain. The Bitcoin Brainwallet Private Key Calculator calculates the standard base58 encoded bitcoin private key from your "brainwallet" passphrase. The private key is the most important bitcoin number. All other numbers can be derived from it. This command uses 3 other functions - all 3 are defined on my user page: 1) brainwallet_exponent() - search for Bitcoin Brainwallet Exponent Calculator 2) brainwallet_checksum() - search for Bitcoin Brainwallet Exponent Calculator 3) b58encode() - search for Bitcoin Brainwallet Base58 Encoder Do make sure you use really strong, unpredictable passphrases (30+ characters)! http:brainwallet.org can be used to check the accuracy of this calculator.

Resize a Terminal Window

Replace 70 with the desired height. Replace 180 with the desired width. I put it in my bashrc, because by default my terminal is too small.

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"

list all opened ports on host

Backup a file with a date-time stamp

1. you don't need to prepend the year with 20 - just use Y instead of y 2. you may want to make your function a bit more secure: buf () { cp ${1?filename not specified}{,$(date +%Y%m%d_%H%M%S)}; }

Save a file you edited in vim without the needed permissions

probably just like 1204, but uses tee as a filter (+ I actually understand how this one works)

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.

Print all lines in a file that are not a certain length

Alternatively, print all the lines that are a certain length: $awk 'length($0)==12 {print}' your_file_name

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