oam/knowledge base/bash.md

Bourne Again SHell

TL;DR

# Run a command or function on exit, kill or error.
trap "rm -f $tempfile" EXIT SIGTERM ERR
trap function-name EXIT SIGTERM ERR

# Disable CTRL-C
trap "" SIGINT

# Re-enable CTRL-C
trap - SIGINT

# Bash 3 and `sh` have no built-in means to convert case of a string, but the
# `awk`, `sed` or `tr` tools can be used instead.
echo $(echo "$name" |  tr '[:upper:]' '[:lower:]' )
echo $(tr '[:upper:]' '[:lower:]' <<< "$name")

# Bash 5 has a special parameter expansion for upper- and lowercasing strings.
echo ${name,,}
echo ${name^^}

Further readings

• Trap
• Upper- or lower-casing strings

Sources

• The Bash trap command