10-LinuxCommands-BestPractices.md

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