extractor/extract

#!/bin/bash
set -euo pipefail
IFS=$'\n\t'

usage() {
  echo "Usage: $0 <archive-file>"
  echo "Extract supported archive formats: .tar.gz, .zip, .rar, .7z, etc."
}

check_command() {
  local cmd="$1"
  if ! command -v "$cmd" &>/dev/null; then
    echo "Error: required command '$cmd' not found."
    exit 3
  fi
}

if [[ $# -eq 0 || "$1" == "--help" ]]; then
  usage
  exit 0
fi

file="$1"

if [[ ! -f "$file" ]]; then
  echo "Error: '$file' is not a valid file."
  exit 2
fi

case "$file" in
  *.tar.bz2)  check_command tar;      tar xjf "$file" ;;
  *.tar.gz)   check_command tar;      tar xzf "$file" ;;
  *.bz2)      check_command bunzip2;  bunzip2 "$file" ;;
  *.rar)      check_command unrar;    unrar x "$file" ;;
  *.gz)       check_command gunzip;   gunzip "$file" ;;
  *.tar)      check_command tar;      tar xf "$file" ;;
  *.tbz2)     check_command tar;      tar xjf "$file" ;;
  *.tgz)      check_command tar;      tar xzf "$file" ;;
  *.zip)      check_command unzip;    unzip "$file" ;;
  *.Z)        check_command uncompress; uncompress "$file" ;;
  *.7z)       check_command 7z;       7z x "$file" ;;
  *)
    echo "Error: '$file' has an unsupported file extension."
    exit 1
    ;;
esac