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In-Place search/replace with datestamped backup
Does an in situ search-replace but leaves a datestamped backup. A variation with more precision: sed -i.`date +%Y%m%d%H%M%S 's/pattern/replace' [filename]

find all active IP addresses in a network

Erase CD RW

'hpc' in the shell - starts a maximum of n compute commands modulo n controlled in parallel, using make
this oneliner uses make and it's jobserver for parallel execution of your script. The '-j' flag for make defines number of subprocesses to launch, '-f' tells make use stdin instead of Makefile. Also make have neat flag '-l', which "Specifies that no new jobs (commands) should be started if there are others jobs running and the load is at least load (a floating-point number)." Also you can use plain Makefile, for better readability: targets = $(subst .png,.jpg,$(wildcard *.png)) $(targets): echo convert $(subst .jpg,.png,$@) $@ all : $(targets)

DVD-Rip
Make backups of your home DVDs easily. Other: mencoder dvd://1 -o "$targetDir/$dvdTitle.avi" -aid "$audioID" -ovc x264 -x264encopts qp=26:frameref=3:bframes=15:direct_pred=auto:cabac:weight_b:partitions=all:8x8dct:me=esa:me_range=24:subq=7:mixed_refs:trellis=2:bitrate=1000:nofast_pskip:threads=0 -oac mp3lame

Find usb device in realtime
Using this command you can track a moment when usb device was attached.

Get your external IP address with a random commandlinefu.com command
There's been so many ways submitted to get your external IP address that I decided we all need a command that will just go pick a random one from the list and run it. This gets a list of "Get your external IP" commands from commanlinefu.com and selects a random one to run. It will run the command and print out which command it used. This is not a serious entry, but it was a learning exercise for me writing it. My personal favourite is "curl icanhazip.com". I really don't think we need any other ways to do this, but if more come you can make use of them with this command ;o). Here's a more useful command that always gets the top voted "External IP" command, but it's not so much fun: $ eval $(curl -s http://www.commandlinefu.com/commands/matching/external/ZXh0ZXJuYWw=/sort-by-votes/plaintext|sed -n '/^# Get your external IP address$/{n;p;q}')

detach remote console for long running operations
Starts midnightcommander and allows you to detach the console; use ctrl-\ to detach Then at a later time you can reconnect using $ dtach -a /tmp/wires-mc In my experience dtach works much better for programs like irssi, mutt, mc, aptitude than screen does.

Query ip pools based on successive netnames via whois
Useful if you f.i. want to block/allow all connections from a certain provider which uses successive netnames for his ip blocks. In this example I used the german Deutsche Telekom which has DTAG-DIAL followed by a number as netname for the dial in pools. There are - as always ;) - different ways to do this. If you have seq available you can use $ net=DTAG-DIAL ; for i in `seq 1 30`; do whois -h whois.ripe.net $net$i | grep '^inetnum:' | sed "s;^.*:;$net$i;" ; done or without seq you can use bash brace expansion $ net=DTAG-DIAL ; for i in {1..30}; do whois -h whois.ripe.net $net$i | grep '^inetnum:' | sed "s;^.*:;$net$i;" ; done or if you like while better than for use something like $ net=DTAG-DIAL ; i=1 ; while true ; do whois -h whois.ripe.net $net$i | grep '^inetnum:' | sed "s;^.*:;$net$i;" ; test $i = 30 && break ; i=$(expr $i + 1) ; done and so on.

decoding Active Directory date format
When Ldapsearch queries an Active directory server, all the dates are shown using a timestamp of 18 digits. This perl regexp decodes them in a more human friendly notation. 11644473600 corresponds to some microsoft epoch.


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