Commands by BigZ (5)

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Delete empty directories
Recursively delete empty directories. Use with care.

Color STDERR in output
This command will take the output of a command and color any STDERR output as a different color (red outline in this case)

Move a folder and merge it with another folder
This will move a folder and merge it with another folder which may contain duplicates. Technically it's just creating hardlinks of everything in the folder, and after it's done, delete the source (with rm -r source/ ) to complete the move. This is much faster than, for example, using rsync to merge folders which would actually copy the entire contents and so for a lot of files would take much longer. This uses macutils gcp port of cp so it can be used on osx/MacOS. If using in linux or some unix where cp includes the ability to create links with -l you can just use cp instead of gcp.

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"

printing barcodes
64 elements max on 16 rows, 4 cols. GNU Barcode will adapt automagically the width and the eight of your elements to fill the page. Standard output format is PostScript.

check open ports without netstat or lsof

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

find out how much space are occuipied by files smaller than 1024K (sic) - improved
The original didn't use -print0 which fails on weird file names eg with spaces. The original parsed the output of 'ls -l' which is always a bad idea.

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"

Mirror every lvol in vg00 in hp-ux 11.31

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