Are there any standard exit status codes in Linux?

Question

A process is considered to have completed correctly in Linux if its exit status was 0.

I've seen that segmentation faults often result in an exit status of 11, though I don't know if this is simply the convention where I work (the apps that failed like that have all been internal) or a standard.

Are there standard exit codes for processes in Linux?

Answer 1

Part 1: Advanced Bash Scripting Guide

As always, the Advanced Bash Scripting Guide has great information: (This was linked in another answer, but to a non-canonical URL.)

1: Catchall for general errors
2: Misuse of shell builtins (according to Bash documentation)
126: Command invoked cannot execute
127: "command not found"
128: Invalid argument to exit
128+n: Fatal error signal "n"
255: Exit status out of range (exit takes only integer args in the range 0 - 255)

Part 2: sysexits.h

The ABSG references sysexits.h.

On Linux:

$ find /usr -name sysexits.h
/usr/include/sysexits.h
$ cat /usr/include/sysexits.h

/*
 * Copyright (c) 1987, 1993
 *  The Regents of the University of California.  All rights reserved.

 (A whole bunch of text left out.)

#define EX_OK           0       /* successful termination */
#define EX__BASE        64      /* base value for error messages */
#define EX_USAGE        64      /* command line usage error */
#define EX_DATAERR      65      /* data format error */
#define EX_NOINPUT      66      /* cannot open input */    
#define EX_NOUSER       67      /* addressee unknown */    
#define EX_NOHOST       68      /* host name unknown */
#define EX_UNAVAILABLE  69      /* service unavailable */
#define EX_SOFTWARE     70      /* internal software error */
#define EX_OSERR        71      /* system error (e.g., can't fork) */
#define EX_OSFILE       72      /* critical OS file missing */
#define EX_CANTCREAT    73      /* can't create (user) output file */
#define EX_IOERR        74      /* input/output error */
#define EX_TEMPFAIL     75      /* temp failure; user is invited to retry */
#define EX_PROTOCOL     76      /* remote error in protocol */
#define EX_NOPERM       77      /* permission denied */
#define EX_CONFIG       78      /* configuration error */

#define EX__MAX 78      /* maximum listed value */

Answer 2

There are no standard exit codes, aside from 0 meaning success. Non-zero doesn't necessarily mean failure either.

stdlib.h does define EXIT_FAILURE as 1 and EXIT_SUCCESS as 0, but that's about it.

The 11 on segfault is interesting, as 11 is the signal number that the kernel uses to kill the process in the event of a segfault. There is likely some mechanism, either in the kernel or in the shell, that translates that into the exit code.

Answer 3

'1' >>> Catchall for general errors

'2' >>> Misuse of shell builtins (according to Bash documentation)

'126'>>> Command invoked cannot execute

'127'>>>"command not found"

'128'>>> Invalid argument to exit

'128+n'>>>Fatal error signal "n"

'130'>>> Script terminated by Control-C

'255'>>>Exit status out of range

This is for bash. However, for other applications, there are different exit codes.

Answer 4

When Linux returns 0, it means success. Anything else means failure, each program has its own exit codes, so it would been quite long to list them all... !

About the 11 error code, it's indeed the segmentation fault number, mostly meaning that the program accessed a memory location that was not assigned.