Linux Best practices

1. some commands default options to use
2. Bash and grep regular expressions

1. some commands default options to use

https://dougrichardson.us/notes/fail-fast-bash-scripting.html but set -o nounset is not usable because empty array are considered unset
always use sed -E
avoid using grep -P as it is not supported on alpine, prefer using -E

2. Bash and grep regular expressions

grep regular expression [A-Za-z] matches by default accentuated character, it you don't want to match them, use the environment variable LC_ALL=POSIX,
- Eg: LC_ALL=POSIX grep -E -q '^[A-Za-z_0-9:]+$'
- I added export LC_ALL=POSIX in all my headers, it can be overridden using a subShell