Problem
You want to generate a SHA digest for a given string.
Solution
Perl has great encryption and digesting algorithms.
In the example tab we use the Digest Perl module.
Example
perl -M'Digest::SHA1 qw(sha1_hex)'
-e '$dig=sha1_hex("my big test"); print "$dign";'
419e6139a21f51a3f2ea1a783cfe536a0dada873