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perl insert character on the first line on your file

Create date-based tgz of current dir, runs in the background, very very cool
This is freaking sweet!!! Here is the full alias, (I didn't want to cause display problems on commandlinefu.com's homepage): $ alias tarred='( ( D=`builtin pwd`; F=$(date +$HOME/`sed "s,[/ ],#,g"

kill some pids without specific pid
pgrep, pkill - look up or signal processes based on name and other attributes

Change/Modify timestamp interactively

add files to existing growable DVD using growisofs
replace "directory name with files to add to DVD" with actual directory containing files you want to add to growable DVD

Mapreduce style processing
parallel can be installed on your central node and can be used to run a command multiple times. In this example, multiple ssh connections are used to run commands. (-j is the number of jobs to run at the same time). The result can then be piped to commands to perform the "reduce" stage. (sort then uniq in this example). This example assumes "keyless ssh login" has been set up between the central node and all machines in the cluster. bashreduce may also do what you want.

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"

diff will usually only take one file from STDIN. This is a method to take the result of two streams and compare with diff. The example I use to compare two iTunes libraries but it is generally applicable.
diff is designed to compare two files. You can also compare directories. In this form, bash uses 'process substitution' in place of a file as an input to diff. Each input to diff can be filtered as you choose. I use find and egrep to select the files to compare.

convert unixtime to human-readable

Find the package that installed a command


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