Not working on Linux

[jonathanlloyd]

When I try to run this on Ubuntu 16.04:

fatal: ambiguous argument 'head': unknown revision or path not in the working tree.
Use '--' to separate paths from revisions, like this:
'git <command> [<revision>...] -- [<file>...]'
date: invalid option -- 'j'
Try 'date --help' for more information.
date: invalid option -- 'j'
Try 'date --help' for more information.
/home/jonathan/git/lgit/aux/selfupdate.sh: line 20: [: : integer expression expected
Nothing to commit...