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commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

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Watch memcache traffic
View all memcache traffic

Console clock
Shows a simple clock in the console -t param removes the watch header Ctrl-c to exit

Show recent earthquakes in Bay Area
To see only earthquakes for today, add another pipe to egrep "`date '+%Y/%m/%d'`"

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

List all groups and the user names that were in each group
"cut" the user names from /etc/passwd and then running a loop over them.

Find Duplicate Files (based on MD5 hash) -- For Mac OS X
This works on Mac OS X using the `md5` command instead of `md5sum`, which works similarly, but has a different output format. Note that this only prints the name of the duplicates, not the original file. This is handy because you can add `| xargs rm` to the end of the command to delete all the duplicates while leaving the original.

Use /dev/full to test language I/O-failsafety
The Linux /dev/full file simulates a "disk full" condition, and can be used to verify how a program handles this situation. In particular, several programming language implementations do not print error diagnostics (nor exit with error status) when I/O errors like this occur, unless the programmer has taken additional steps. That is, simple code in these languages does not fail safely. In addition to Perl, C, C++, Tcl, and Lua (for some functions) also appear not to fail safely.

Search for a string inside all files in the current directory
options: -n line nbrs, -i ignore case, -s no "doesn't exist", -I ignore binary args: * for all files of current dir (not hidden), .[!.]* for all hidden files I don't include by default the -R (recursive) option, which is not always useful. You add it by hand when needed.

list block devices
Shows all block devices in a tree with descruptions of what they are.

1:1 copy of a volume
copies all files from the source disk / (skipping boundaries of mouted -in volumes) to /mnt/mydisk. Logical links are being preserved as well as devices, pipes etc. This can copy a MacOS X or Linux volume and keep it bootable. Note: its not suited to copy files with MacOS 9 style resources.


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