Bash #cheatsheet #tips

bash.md

Bash

Language convention

tooling

CLI tools

beautysh (github)

This program takes upon itself the hard task of beautifying Bash scripts (yeesh).

install with pip install beautysh

shellcheck (github)

A shell script static analysis tool

install with cabal update ; cabal install ShellCheck

relevant atom packages

• atom-beautify
• linter
• linter-shellcheck

tips

#!/bin/bash

### Run in parallel
for c in $commands_to_run
do
    c &
done

FAIL=0

echo "start waiting at $(date +%s)"
for job in $(jobs -p)
do
  echo "$job"
  wait "$job" || let "FAIL+=1"
done

echo "$FAIL"
echo "done wait (TS : $(date +%s))"

### process a file line by line
in="${1:-filename}"
[ ! -f "$in" ] && { echo "$0 - File $in not found."; exit 1; }
while IFS= read -r line
do
  # avoid comments
  [[ $line = \#* ]] && continue
  echo "Process $line"
done < "${in}"

### Get pipestatus
echo "running a piped command" | sort | uniq | tee out.file
pipe_status_to_check=( ${PIPESTATUS[*]} ) # save it to prevent overiding
if [ ${pipe_status_to_check[0]} -ne "0" ];
then
  echo "echo failed! WTF"
fi

### find cheatsheet
find -L -type f -empty # -L for follow symlink
find -type f ! -empty # negate the empty condition

### create symlink for all executable files in $home/bin
for f in ./*; do
	if [[ -x "$f" ]]; then
		ln -sf "$(pwd)/$(basename "$f")" "$HOME/bin/$(basename "$f")"
	fi
donel