# flock > Manage locks from shell scripts. > It can be used to ensure that only one process of a command is running. > More information: . - Run a command with a file lock as soon as the lock is not required by others: `flock {{path/to/lock.lock}} --command "{{command}}"` - Run a command with a file lock, and exit if the lock doesn't exist: `flock {{path/to/lock.lock}} --nonblock --command "{{command}}"` - Run a command with a file lock, and exit with a specific error code if the lock doesn't exist: `flock {{path/to/lock.lock}} --nonblock --conflict-exit-code {{error_code}} -c "{{command}}"`