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Mouse Tracking
Will track your mouse and save it to a file. You can use gnuplot to graph it: $ gnuplot -persist

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"

Print every Nth line
Sometimes commands give you too much feedback. Perhaps 1/100th might be enough. If so, every() is for you. $ my_verbose_command | every 100 will print every 100th line of output. Specifically, it will print lines 100, 200, 300, etc If you use a negative argument it will print the *first* of a block, $ my_verbose_command | every -100 It will print lines 1, 101, 201, 301, etc The function wraps up this useful sed snippet: $ ... | sed -n '0~100p' don't print anything by default $ sed -n starting at line 0, then every hundred lines ( ~100 ) print. $ '0~100p' There's also some bash magic to test if the number is negative: we want character 0, length 1, of variable N. $ ${N:0:1} If it *is* negative, strip off the first character ${N:1} is character 1 onwards (second actual character).

Phrack 66 is out, but the .tar.gz is not there yet on phrack.org's website
Nice reading in the morning on the way to work, but sadly the .tar.gz for the whole issue 66 is not on phrack's website yet. So use wget to download.

Draw kernel module dependancy graph.
parse "lsmod" output to "dot" format and pass it to "display". Without perl!

Install your ssh key file on a remote system

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

Prepend a text to a file.
Prepend text to a file. It doen't need temporary files, ed or sed.

Efficient count files in directory (no recursion)
$ time perl -e 'if(opendir D,"."){@a=readdir D;print $#a - 1,"\n"}' 205413 real 0m0.497s user 0m0.220s sys 0m0.268s $ time { ls |wc -l; } 205413 real 0m3.776s user 0m3.340s sys 0m0.424s ********* ** EDIT: turns out this perl liner is mostly masturbation. this is slightly faster: $ find . -maxdepth 1 | wc -l sh-3.2$ time { find . -maxdepth 1|wc -l; } 205414 real 0m0.456s user 0m0.116s sys 0m0.328s ** EDIT: now a slightly faster perl version $ perl -e 'if(opendir D,"."){++$c foreach readdir D}print $c-1,"\n"' sh-3.2$ time perl -e 'if(opendir D,"."){++$c foreach readdir D}print $c-1,"\n"' 205414 real 0m0.415s user 0m0.176s sys 0m0.232s

Slightly better compressed archives
Avoids creating useless directory entries in archive, and sorts files by (roughly) extension, which is likely to group similar files together for better compression. 1%-5% improvement.


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