executable_dshell

#!/usr/bin/env bash
set -euo pipefail

CONTAINER=""
USER="root"

usage() {
  cat << EOF
Usage: dshell CONTAINER [OPTIONS]

Open an interactive shell in a Docker container easily.

Arguments:
  CONTAINER         Docker container name 

Options:
  -u, --user USER   User to run the shell as (default: root)
  -h, --help        Display this help message

Examples:
  dshell c1
  dshell c1 --user myuser

EOF
}

generate_shell_command() {
    local cmd
    local login_path
    local bash_path

    if login_path=$(docker exec "${CONTAINER}" which login 2>/dev/null); then
        cmd="docker exec -ti -u root ${CONTAINER} ${login_path} -f ${USER}"
    elif bash_path=$(docker exec "${CONTAINER}" which bash 2>/dev/null); then
        cmd="docker exec -ti -u ${USER} ${CONTAINER} ${bash_path} -l"
    else
        cmd="docker exec -ti -u ${USER} ${CONTAINER} sh -l"
    fi
    echo "$cmd"
}

while [[ $# -gt 0 ]]; do
  case $1 in
    -h|--help) 
      usage ; exit 0 ;;
    -u|--user)
      USER="$2"; shift 2 ;;
    -*) 
      echo -e "Error: Unknown option: $1\n"; usage ; exit 1 ;;
    *)
      if [[ -n "$CONTAINER" ]]; then
        echo -e "Error: Too many arguments\n"; usage ; exit 1
      fi
      CONTAINER="$1"; shift ;;
  esac
done

if [[ -z "${CONTAINER}" ]]; then
  echo -e "Error: CONTAINER argument is required\n"; usage; exit 1
fi

echo -e "Opening shell in container '${CONTAINER}' as user '${USER}'\n"
exec $(generate_shell_command)