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New page: = Exist Status = Each process that executes on a Linux system leaves a whole number ''exit code'' (or ''exit status'', ''result code'', or ''error code'') when it terminates. The value o...
= Exist Status =
Each process that executes on a Linux system leaves a whole number ''exit code'' (or ''exit status'', ''result code'', or ''error code'') when it terminates.
The value of the exit code is usually 0 if no errors were encountered, or non-zero if an error was encountered. The meaning of specific codes varies program-by-program; see the documentation (such as the man page) for a program to determine the meaning of those codes.
In a multi-command pipeline, the exit status of the last command is used as the exit status for the entire pipeline. (In [[BASH]] documentation, the term ''pipeline'' is used to refer to any single command or sequence of commands; see the BASH manpage for details).
= Retrieving Exist Status =
BASH places the exit status of the most recently-executed pipeline in the special variable <code>$?</code>. You can view the value of this variable using the <code>echo</code> command:
$ ls /tmp >/dev/null
$ echo $?
0
$ ls /temp >/dev/null
ls: cannot access /temp: No such file or directory
$ echo $?
2
= Setting the Exit Status when Exiting from a Shell Script =
The BASH <code>exit</code> command can be used with a whole-number numeric positional argument to exit a script with a particular status code. For example:
exit 2
Will exit the script with an exit code of 2.
= Exit Codes and Flow Control =
Exit codes are used extensively with the [[BASH Flow Control]] operators.
[[Category:BASH]][[CATEGORY:Linux]]
Each process that executes on a Linux system leaves a whole number ''exit code'' (or ''exit status'', ''result code'', or ''error code'') when it terminates.
The value of the exit code is usually 0 if no errors were encountered, or non-zero if an error was encountered. The meaning of specific codes varies program-by-program; see the documentation (such as the man page) for a program to determine the meaning of those codes.
In a multi-command pipeline, the exit status of the last command is used as the exit status for the entire pipeline. (In [[BASH]] documentation, the term ''pipeline'' is used to refer to any single command or sequence of commands; see the BASH manpage for details).
= Retrieving Exist Status =
BASH places the exit status of the most recently-executed pipeline in the special variable <code>$?</code>. You can view the value of this variable using the <code>echo</code> command:
$ ls /tmp >/dev/null
$ echo $?
0
$ ls /temp >/dev/null
ls: cannot access /temp: No such file or directory
$ echo $?
2
= Setting the Exit Status when Exiting from a Shell Script =
The BASH <code>exit</code> command can be used with a whole-number numeric positional argument to exit a script with a particular status code. For example:
exit 2
Will exit the script with an exit code of 2.
= Exit Codes and Flow Control =
Exit codes are used extensively with the [[BASH Flow Control]] operators.
[[Category:BASH]][[CATEGORY:Linux]]
