WARNING!!! ALL DATA WILL BE LOST!!! This command should ONLY be run on drives that are meant to be wiped. Data destruction will result from running this command with the '-w' switch. You may run this command with the '-n' switch in place of '-w' if you want to retain all data on the drive, however, the test won't be as detailed, since the '-n' switch provides a non-destructive read-write mode only, whereas '-w' switch actually writes patterns while scanning for bad blocks.

I used this command to recursively gather all mp3 files that were previously imported into their own directories (sorted by band name) in Songbird.

-geometry (preserves values of height and width given, and aspect ratio). WARNING: While 'resize' creates resized copies of original files, 'mogrify' works on the original files, replacing them. It will overwrite the source files, use with caution, and backup regularly.

gpg command to encrypt a file on the command line.

gpg command to decrypt a previously encrypted file on the command line. Can be optionally made into an alias: alias decrypt='gpg --output foo.txt --decrypt foo.txt.pgp'