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SYSEXITS (3) | C library functions | Unix Manual Pages | :man


sysexits - preferable exit codes for programs


See Also


.In sysexits.h


According to style(9), it is not a good practice to call exit(3) with arbitrary values to indicate a failure condition when ending a program. Instead, the pre-defined exit codes from sysexits should be used, so the caller of the process can get a rough estimation about the failure class without looking up the source code.

The successful exit is always indicated by a status of 0, or EX_OK. Error numbers begin at EX__BASE to reduce the possibility of clashing with other exit statuses that random programs may already return. The meaning of the codes is approximately as follows:

EX_USAGE(64) The command was used incorrectly, e.g., with the wrong number of arguments, a bad flag, a bad syntax in a parameter, or whatever.
EX_DATAERR(65) The input data was incorrect in some way. This should only be used for user’s data and not system files.
EX_NOINPUT(66) An input file (not a system file) did not exist or was not readable. This could also include errors like "No message" to a mailer (if it cared to catch it).
EX_NOUSER(67) The user specified did not exist. This might be used for mail addresses or remote logins.
EX_NOHOST(68) The host specified did not exist. This is used in mail addresses or network requests.
EX_UNAVAILABLE(69) A service is unavailable. This can occur if a support program or file does not exist. This can also be used as a catchall message when something you wanted to do does not work, but you do not know why.
EX_SOFTWARE(70) An internal software error has been detected. This should be limited to non-operating system related errors as possible.
EX_OSERR(71) An operating system error has been detected. This is intended to be used for such things as "cannot fork", "cannot create pipe", or the like. It includes things like getuid returning a user that does not exist in the passwd file.
EX_OSFILE(72) Some system file (e.g., /etc/passwd, /var/run/utmp, etc.) does not exist, cannot be opened, or has some sort of error (e.g., syntax error).
EX_CANTCREAT(73) A (user specified) output file cannot be created.
EX_IOERR(74) An error occurred while doing I/O on some file.
EX_TEMPFAIL(75) Temporary failure, indicating something that is not really an error. In sendmail, this means that a mailer (e.g.) could not create a connection, and the request should be reattempted later.
EX_PROTOCOL(76) The remote system returned something that was "not possible" during a protocol exchange.
EX_NOPERM(77) You did not have sufficient permission to perform the operation. This is not intended for file system problems, which should use EX_NOINPUT or EX_CANTCREAT, but rather for higher level permissions.
EX_CONFIG(78) Something was found in an unconfigured or misconfigured state.

The numerical values corresponding to the symbolical ones are given in parenthesis for easy reference.


err(3), exit(3), style(9)




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