mkunit path

Create a systemd path unit to trigger on file/directory changes.

mkunit path <name> [flags]

Description

The path command creates a .path unit file for monitoring filesystem paths. When the watched path changes, systemd triggers the associated service. This is useful for processing uploaded files, reloading configurations, or reacting to log file changes.

Arguments

Argument Description
<name> Name of the path unit (without .path extension)

Flags

Flag Description Default
--unit <name> Service unit to trigger <name>.service
--path-exists <path> Trigger when path exists —
--path-exists-glob <glob> Trigger when glob matches any files —
--path-changed <path> Trigger when path is modified —
--path-modified <path> Trigger when path is written to —
--directory-not-empty <path> Trigger when directory has files —
--make-directory Create the watched directory if missing false
--directory-mode <mode> Mode for created directory (octal) 0755
--description <text> Human-readable description Auto-generated
--system Create a system path unit false
--install Install the unit file false
--start Start the path watcher false
--enable Enable on boot false
--dry-run Print without writing false

Watch Types

Type Triggers When
PathExists File or directory exists (checked on timer start and periodically)
PathExistsGlob Any files match the glob pattern
PathChanged File is renamed, deleted, or attributes change
PathModified File content is written (close after write)
DirectoryNotEmpty Directory contains at least one file

Examples

Watch for new files in upload directory

mkunit path upload-processor \
  --directory-not-empty /var/uploads \
  --make-directory \
  --install --start

Trigger processing when config changes

mkunit path config-reload \
  --path-modified /etc/myapp/config.yaml \
  --unit myapp-reload.service \
  --install --enable

React to log file modifications

mkunit path log-analyzer \
  --path-modified /var/log/myapp/access.log \
  --install --start

Watch for lock file (simple semaphore)

mkunit path trigger-job \
  --path-exists /tmp/run-job.trigger \
  --install --enable

Process matching files with glob

mkunit path csv-importer \
  --path-exists-glob "/var/data/incoming/*.csv" \
  --install --start

Watch multiple conditions

# First create the path unit
mkunit path multi-watch \
  --path-modified /etc/myapp/config.yaml \
  --directory-not-empty /var/spool/myapp \
  --install
Note

Path units use inotify under the hood. For high-volume directories, consider using a timer instead to batch process files periodically.

See Also