Shell scripts are the recommended choice for ZEDLETs that mostly call
other utilities and do relatively little data manipulation.
Shell scripts MUST work on both bash and dash.
Shell scripts MUST run cleanly through ShellCheck:
http://www.shellcheck.net/
General functions reside in "zed-functions.sh". Use them where applicable.
Additional references that may be of use:
Google Shell Style Guide
https://github.com/google/styleguide/blob/gh-pages/shell.xml
Dash as /bin/sh
https://wiki.ubuntu.com/DashAsBinSh
Common shell script mistakes
http://www.pixelbeat.org/programming/shell_script_mistakes.html
Filenames and Pathnames in Shell: How to do it Correctly
http://www.dwheeler.com/essays/filenames-in-shell.html
Autoconf: Portable Shell Programming
https://www.gnu.org/software/autoconf/manual/autoconf.html#Portable-Shell
Please BE CONSISTENT with the existing style, check for errors,
minimize dependencies where possible, try to be portable,
and comment anything non-obvious. Festina lente.