flock:tldr:88093

flock: Run a command with a file lock, and exit with a specific error code if the lock doesn't exist.

flock

$ flock ${path-to-lock-lock} --nonblock --conflict-exit-code ${error_code} -c "${command}"

try on your machine

This command is using the flock utility in Unix-based systems to acquire an exclusive lock on a specified file or resource, execute a command, and release the lock afterward.

Here is how the different parts of the command work:

${path-to-lock-lock}: This should be replaced with the path to the lock file or resource you want to acquire exclusive access to.
--nonblock: This flag instructs flock to not wait if the lock is currently held by another process. Instead, it will exit immediately with a specific exit code (${error_code}) indicating a conflict.
--conflict-exit-code ${error_code}: This flag sets the exit code for flock when a conflict occurs. ${error_code} should be replaced with an actual numeric value that you want to use as the exit code.
-c "${command}": This is the command that will be executed while holding the lock. ${command} should be replaced with the actual command you want to run within the lock.

In summary, this command attempts to acquire a lock on a specified file, runs a command in that locked state, and exits immediately with a specific exit code if the lock is already held by another process.

This explanation was created by an AI. In most cases those are correct. But please always be careful and never run a command you are not sure if it is safe.

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