Bash
rm_str() in Bash: Remove a Substring From a String
Delete every occurrence of a substring with one Bash parameter expansion, no sed or tr needed, and the quoting mistakes that make it go wrong.
Author
Nawawi Jamili
Bash
lcfirst() in Bash: Lowercase the First Character
lcfirst() in Bash with ${var,} and a Bash 3.2 fallback, used for PascalCase to camelCase, plus a fix for names that begin with an acronym.
Bash
str_repeat() in Bash: Repeat a String N Times
A str_repeat() for Bash that stays fast at millions of copies, why the common printf trick slows down, and the two bugs in the 2009 version.
Bash
is_num() in Bash: Check if a Value Is a Number
Check that input is a whole number, a signed integer or a decimal before doing arithmetic, and avoid the octal, empty-string and injection problems in (( )).