set 命令

常用示例

说明

set is a shell builtin that controls shell options and positional parameters. Options modify shell behavior for scripting, debugging, and interactive use. Use - to enable an option and + to disable it. When invoked without arguments, set displays all shell variables and functions. With -- followed by arguments, it sets the positional parameters ($1, $2, etc.) to the provided values. The combination set -euo pipefail is a common "strict mode" for shell scripts that causes immediate exit on errors, undefined variable references, or pipeline failures—catching bugs early and preventing silent failures.

参数

-a (allexport)

Export all created or modified variables and functions

-b (notify)

Report terminated background job status immediately

-e (errexit)

Exit immediately if a command returns non-zero status

-f (noglob)

Disable filename expansion (globbing)

-h (hashall)

Remember command locations as they are looked up

-k (keyword)

Place all assignment arguments in the environment

-m (monitor)

Enable job control

-n (noexec)

Read commands but do not execute them (syntax check)

-p (privileged)

Enable privileged mode

-t (onecmd)

Exit after reading and executing one command

-u (nounset)

Treat unset variables as an error during expansion

-v (verbose)

Print shell input lines as they are read

-x (xtrace)

Print commands and arguments before execution

-B (braceexpand)

Enable brace expansion (default on)

-C (noclobber)

Prevent overwriting files with output redirection

-E (errtrace)

ERR trap is inherited by shell functions and subshells

-H (histexpand)

Enable ! style history substitution

-P (physical)

Do not resolve symbolic links for commands like cd

-T (functrace)

DEBUG and RETURN traps inherited by functions

-o pipefail

Pipeline returns status of last non-zero command

--

End of options; remaining args become positional parameters