A but.sh template to generate a systemd unit file (such as .service)

README.md

systemd-unit file buttemplate

This is a but.sh template for creating a systemd unit file (.automount, .device, .mount, .path, .scope, .service, .slice, .socket, .swap, .timer, ...)

Prerequisites

This, of course, requires but.sh The template itself requires only bash and gnu-coreutils.

Variables

The valid section names are:

• Automount
• Install
• Mount
• Path
• Scope
• Service
• Slice
• Socket
• Swap
• Timer
• Unit

Variables are named like <section_name_allcaps>_<option_name>, where the option name is also all-caps and words separated by underscores. (Example: SERVICE_GUESS_MAIN_PID would match GuessMainPID in the [Service] section.)

If any variables are defined in a given section, the section is created; they are defined in the alphabetical order.

Examples

All of the .env files in this gist are examples for unit files of the stated type.

Downloading

wget https://gist.github.com/nealian/4219ce02189e3abaad3c66dcaa1b2c3b/raw/systemd-unit.buttemplate{,.src}

Usage

but.sh systemd-unit.buttemplate -c systemd-unit.buttemplate.src -c unit.env -o /usr/lib/systemd/system/unit.service

automount.env

AUTOMOUNT_WHERE=/path/to/automount
AUTOMOUNT_DIRECTORY_MODE=0750

INSTALL_WANTED_BY=multi-user.target

UNIT_DESCRIPTION="Automount /path/to/automount"

mount.env

MOUNT_WHAT="nfs.example.com:/export/foo"
MOUNT_WHERE=/path/to/mount
MOUNT_TYPE=nfs
MOUNT_DIRECTORY_MODE=0750

INSTALL_WANTED_BY=multi-user.target

UNIT_DESCRIPTION="Mount /path/to/mount"

path.env

PATH_PATHCHANGED=/path/to/watch

INSTALL_WANTED_BY=default.target

service.env

SERVICE_TYPE=simple
SERVICE_EXEC_START="/path/to/binary %i"
SERVICE_STANDARD_INPUT=socket
SERVICE_STANDARD_ERROR=journal

UNIT_DESCRIPTION="Mount /path/to/mount"
UNIT_REQUIRES=foo.socket

socket.env

SOCKET_LISTEN_STREAM="127.0.0.1:31337"
SOCKET_ACCEPT=yes

INSTALL_WANTED_BY=sockets.target

UNIT_DESCRIPTION="Socket for per-socket service"

swap.env

SWAP_WHAT=/dev/sda3

INSTALL_WANTED_BY=swap.target

UNIT_DESCRIPTION="Swap at /dev/sda3"

systemd-unit.buttemplate

$(for x in ${SECTIONS_SYSTEMD[*]}; do
  opts=$(eval echo "\${!${x^^}_*}")
  if [[ -n "${opts}" ]]; then
    echo "[${x}]";
    for y in ${opts}; do
      echo "$(echo ${y##${x^^}_} | sed -r 's,^([A-Z]+)(_?),\L\u\1\2,;s,_([A-Z]+),\L\u\1,g' | sed "$(for repl in ${nosep[*],,}; do echo "s,${repl^},${repl^^},g;"; done)" | sed 's,SELINUX,SELinux,g')=${!y}";
    done;
    echo;
  fi;
done)

systemd-unit.buttemplate.src

declare -a SECTIONS_SYSTEMD

SECTIONS_SYSTEMD=(Automount Install Mount Path Scope Service Slice Socket Swap Timer Unit)

declare -a nosep=(TTYVT TTYV TTY STACK SIGPIPE SIGPENDING SIGKILL SIGHUP SELINUX RTTIME RTPRIO RSS PID PAM OOM NPROX NOFILE NICE MSGQUEUE MEMLOCK LOCKS IPTTL IPTOS IP IO FSIZE FIFO DATA CPU CORE AS AC)

timer.env

TIMER_ON_BOOT_SEC=15min
TIMER_ON_UNIT_ACTIVE_SEC=1w

INSTALL_WANTED_BY=timers.target

UNIT_DESCRIPTION="Run example service 15 minutes after boot and again every week while the system is running"