Linux terminal command execution time monitoring and limit: detailed explanation of time
and timeout
commands
When working in a Linux terminal, it is often necessary to monitor the execution time of commands or limit their running time. time
and timeout
commands are powerful tools for completing these tasks. This tutorial will explore how to use both commands effectively and provide practical examples.
Use time
command
time
command is used to measure the execution time of a specified command or process. It provides information about the actual time, user time, and system time when the command is used. Actual time represents the actual elapsed time, user time represents the CPU time consumed by the command, and system time represents the time spent on the command execution.
grammar:
time [options] command
Example: Suppose you want to measure the time it takes to execute the ls
command:
time ls
The output will provide the following information:
<code>real 0m0.005s user 0m0.001s sys 0m0.003s</code>
In this example, the actual time is the actual time of command execution, while the user time and system time represent the CPU time spent in user mode and system mode, respectively.
Use timeout
command
The timeout
command allows you to run commands with specified time limits. If the command does not complete within the specified time, timeout
will terminate it. This is especially useful when dealing with commands that may be suspended or run infinitely.
grammar:
timeout [options] duration command
Example: Suppose you want to limit the execution time of a possible time-consuming command (such as a backup script) to 1 minute:
timeout 1m ./backup_script.sh
If backup_script.sh
is completed within 1 minute, the command will end naturally. However, if it exceeds the time limit, timeout
will terminate it.
By default, timeout
sends a SIGTERM signal to the command when the time limit is reached. You can also use the -s
( --signal
) option to specify the signal to be sent.
Use time
and timeout
in combination
You can also combine time
and timeout
commands to measure the execution time of a command in a time-limited environment.
timeout 10s time ./long_running_command.sh
In this example, the timeout
command ensures that the time
command (which measures execution time) does not run infinitely. Execution will terminate after 10 seconds and time
output will provide insights into the resources used during that time period.
in conclusion
time
and timeout
commands are valuable tools for managing the execution time of commands in Linux. time
command helps you understand the resource utilization of commands, while the timeout
command allows you to control the execution time of commands to prevent them from running infinitely. By mastering these commands, you can better manage terminal tasks and improve your overall efficiency as a Linux user.
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