Hi,

Two quick patches. They switch our eclasses to use bash built-ins
whenever possible to avoid the whole overhead of calling external tools
and piping variables to them to perform simple tasks.

First replaces the 'sed' call in _python_rewrite_shebang() with local
variable substitution to remove the CR.

Second replaces both uses of 'head -n 1' with simple 'read' call to
obtain the first line.

-- 
Best regards,
Michał Górny