initial commit

Before-After/README.md

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+# Execute a unit before and after another one
+
+## Use case
+
+In this example, I wanted to mount a file system (/mnt/test).
+But before mounting the filesystem, I wanted to make a backup of it.
+And after, I want to restore the filesystem from the previous backup.
+In addition to that, the backup is stored on another filesystem that needs to be mounted too.
+
+## Install
+
+```sh
+./install.sh
+```
+
+## Test
+
+```sh
+./test.sh
+cat /mnt/test/witness
+```

Before-After/backup-mnt-test.service

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+[Unit]
+Description=Backup the content of /mnt/test
+Documentation=https://github.com/nmasse-itix/Systemd-Examples
+Before=mnt-test.mount
+RequiresMountsFor=/mnt/backup
+
+[Service]
+Type=oneshot
+UMask=077
+ExecStart=tar -cf /mnt/backup/mnt-test.tar -C /mnt/test .

Before-After/common.env

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+declare -a UNITS=(
+    *.target
+    *.service
+    *.mount
+)

Before-After/custom.target

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+[Unit]
+Description=Custom Target
+Documentation=https://github.com/nmasse-itix/Systemd-Examples
+AllowIsolate=no

Before-After/install.sh

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+#!/bin/bash
+
+set -Eeuo pipefail
+
+. common.env
+
+for unit in "${UNITS[@]}"; do
+  echo "Installing $unit..."
+  sudo cp -r --preserve=mode "$unit" "/etc/systemd/system/$unit"
+done
+
+echo "Reloading systemd..."
+sudo systemctl daemon-reload
+
+for unit in "${UNITS[@]}"; do
+  if grep -Fqx '[Install]' "$unit"; then
+    echo "Installing $unit..."
+    sudo systemctl enable "$unit"
+  fi
+done

Before-After/mnt-backup.mount

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+[Unit]
+Description=Mount the "/mnt/backup" filesystem
+Documentation=https://github.com/nmasse-itix/Systemd-Examples
+
+[Mount]
+What=tmpfs
+Where=/mnt/backup
+Type=tmpfs
+Options=context=system_u:object_r:container_file_t:s0
+
+[Install]
+WantedBy=custom.target

Before-After/mnt-test.mount

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+[Unit]
+Description=Mount the "/mnt/test" filesystem
+Documentation=https://github.com/nmasse-itix/Systemd-Examples
+After=backup-mnt-test.service
+Requires=backup-mnt-test.service
+Before=restore-mnt-test.service
+Wants=restore-mnt-test.service
+
+[Mount]
+What=tmpfs
+Where=/mnt/test
+Type=tmpfs
+
+[Install]
+WantedBy=custom.target

Before-After/restore-mnt-test.service

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+[Unit]
+Description=Restore the "/mnt/test" filesystem
+Documentation=https://github.com/nmasse-itix/Systemd-Examples
+After=mnt-test.mount
+Requires=mnt-test.mount
+RequiresMountsFor=/mnt/backup
+
+[Service]
+Type=oneshot
+ExecStart=tar -xf /mnt/backup/mnt-test.tar -C /mnt/test
+ExecStartPost=rm -f /mnt/backup/mnt-test.tar

Before-After/test.sh

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+#!/bin/bash
+
+set -Eeuo pipefail
+
+. common.env
+
+sudo systemctl stop mnt-test.mount
+sudo systemctl stop mnt-backup.mount
+
+sudo rm -f /mnt/test/witness /mnt/backup/mnt-test.tar
+sudo mkdir -p /mnt/test /mnt/backup
+echo "Hello, World!" | sudo tee /mnt/test/witness > /dev/null
+
+( sleep 1 ; sudo systemctl start custom.target ) &
+
+declare -a journalctl_args=()
+for unit in "${UNITS[@]}"; do
+  journalctl_args+=( -u "$unit" )
+done
+sudo journalctl --since=now "${journalctl_args[@]}" -f

LICENSE

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+The MIT License (MIT)
+
+Copyright © 2025 Nicolas MASSE
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

README.md

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+# Systemd examples
+
+This repository contains various examples of Systemd units that I had to craft over time.
+
+## License
+
+MIT