Development

Code Standards

In general, coding standards follow language-defined specificaitons–PEP8 and POSIX for example.

Requirements:

• ALL new features MUST come with test units.

• Keep commits small, well-documented, and signed.

Shell Notes

See also

These notes apply only to shell library development!

This library is built with many edge cases in mind. In practice, it’s unlikely these situations will even be encountered. For example, [0-9] is not used in the extremely unlikely chance it is not expanded to 0123456789. The typical script /should/ prefer the shorter and more readable form.

Refer to Shell Samples for general script writing tips.

printf vs. echo:

The use of echo should typically be avoided because it can have unexpected behavior between different shells when certain values (leading options, backslashes, etc.) are provided.

find w/ xargs:

The -print0 and -0 options are GNU extensions and should not be used. Additionally, piping find directly into xargs can be problematic. To address these issues, the following form should be used:

find ... | sed 's/./\\&/g' | xargs command

quotes:

Use them!

case:

A leading ( for each component is optional. For the sake of syntax highlighting and making a choice… it’s not optional.

subshells:

Do not use subshells unless absolutely necessary. These can potentially hide errors, return codes, etc.

Note: This is why version_compare() includes the following additional logic:

# Check for valid responses or bail early
case "$_cmp" in
    (1|0|2) :;;     # Expected (valid) resturn values
    (*) die "$_cmp" 'version comparison failed';;
esac

[0-9] vs. [012..]:

In case statements, spell out [0123456789]) instead of [0-9]). Some very obsure locales have atypical characters between 0 and 9.

die():

In some cases, it will be appropriate to invoke die() from within the library. However, it should be avoided whenever possible. It is better to avoid situations where an early failure may be needed (i.e. prefer shorter/simpler functions over kitchen-sink solutions)