timeout

Additional Notes

timeout runs another command with a time limit. If the command is still running when the limit is reached, timeout sends it a signal.

Use it in scripts, tests, network checks, downloads, and automation jobs where a command should not hang forever.

Syntax

timeout [options] duration command [arguments...]

Parameters

• options: Flags that change how timeout behaves.
• duration: Time limit such as 10s, 2m, 1h, or 1d. Seconds are the default.
• command: Command to run.
• arguments: Arguments passed to the command.

Common Options

• -s SIGNAL: Send a specific signal when time expires.
• -k DURATION: Force kill after an additional delay.
• --preserve-status: Return the command's status when possible.
• --foreground: Let an interactive command use the foreground terminal.
• -v: Print a message when timeout sends a signal.

Examples

timeout 10s curl https://example.com

Stop curl if it runs longer than 10 seconds.

timeout -k 5s 1m ./job.sh

Send the default timeout signal after 1 minute, then force kill 5 seconds later if needed.

timeout -s INT 30s ./server-test.sh

Send INT instead of the default TERM when time expires.

Practical Notes

• Without --preserve-status, a timed-out command usually returns status 124.
• Status 125 means timeout itself failed.
• Status 126 means the command was found but could not run.
• Status 127 means the command was not found.
• Status 137 usually means KILL was used.
• Put timeout options before the duration and command.