Useful BASH Snippets

Frequently Google'd bash snippets. I don't use these often enough to have them memorized.

add #!/bin/bash to the top of bash scripts or else you can run them with bash [filename].sh

Arrays

• see For Loops

Conditionals

if [ ! -d "node_modules" ]; then
  echo "node_modules directory exists"
fi

For Loops

array=( one two three )
for i in "${array[@]}"
do
	echo $i
done
# one
# two
# tree

Variables

FOO="bar"
BAZ="${FOO}baz"

echo "${BAZ}"
# barbaz

• don't add spaces before/after equal, it will throw an error

While loops and STDIN

 while read line
  do
    echo "${line}"
    if [[ "$line" =~ "$LINT_DIR" ]]; then
        BUILD_RULES=true
        break
    fi
  done < "${1:-/dev/stdin}"

• can't set stdin as a var!