For reading .chm files on MAC OS, get CHMOX! It’s free and dead cool.

Verify SHA1 checksums

Handy little checker on the above page:
#! /bin/bash

hash=$(openssl sha1 $1)
if [ "SHA1(${1})= $2" = "${hash}" ]; then echo "Key is valid."; else echo "Key is _not_ valid!!!"; fi

Great resource for awk examples, and at the bottom of this page some useful greps.

And the classic SSH public keys. Handy starter for crontabs here.

To create a tarball use this syntax: tar -cf [name of tarball].tar [list of files or directories] To gzip it, do:  gzip -9 [file].tar.

Then to unpack the tarball, do: gzip -d file.gz for zip files, and tar -xvf file.tar for .tar files. If you’ve got a .tgz file, just do tar -xvzf file.tgz.