Bash Script exit kodları

echo $?

Herhangi bir bash/shell script’i çalıştıktan sonra, iş bitiminde geriye bir exit code döner. Genelde eğer işlem başarılıysa bu değer 0 değilse 1 ya da duruma göre başka bir sayı döner. Bu sayıların ne anlama geldiğini merak ettim :)

Örneğin ls ile directory listesi aldınız. Eğer sonrasında; echo $? yaparsanız ls komutunun iş bitiminde exit coder olarak ne döndüğünü görürsünüz. Denemek için olmayan bir dizinin listesini almaya çalışın:

ls /foo/bar/baz/bat/voo
# ls: /foo/bar/baz/bat/voo: No such file or directory
echo $?
1

1 geldi. Peki bu sayı nereden geliyor ve manası ne? Hemen;

cat /usr/include/sysexits.h

diyoruz ve:

/*
 * Copyright (c) 1987, 1993
 *  The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *  This product includes software developed by the University of
 *  California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *  @(#)sysexits.h  8.1 (Berkeley) 6/2/93
 */

#ifndef _SYSEXITS_H_
#define _SYSEXITS_H_

/*
 *  SYSEXITS.H -- Exit status codes for system programs.
 *
 *  This include file attempts to categorize possible error
 *  exit statuses for system programs, notably delivermail
 *  and the Berkeley network.
 *
 *  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 -- 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 -- The input data was incorrect in some way.
 *      This should only be used for user's data & not
 *      system files.
 *  EX_NOINPUT -- 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 -- The user specified did not exist.  This might
 *      be used for mail addresses or remote logins.
 *  EX_NOHOST -- The host specified did not exist.  This is used
 *      in mail addresses or network requests.
 *  EX_UNAVAILABLE -- 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 doesn't work, but you don't know
 *      why.
 *  EX_SOFTWARE -- An internal software error has been detected.
 *      This should be limited to non-operating system related
 *      errors as possible.
 *  EX_OSERR -- 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 -- Some system file (e.g., /etc/passwd, /etc/utmp,
 *      etc.) does not exist, cannot be opened, or has some
 *      sort of error (e.g., syntax error).
 *  EX_CANTCREAT -- A (user specified) output file cannot be
 *      created.
 *  EX_IOERR -- An error occurred while doing I/O on some file.
 *  EX_TEMPFAIL -- 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 -- the remote system returned something that
 *      was "not possible" during a protocol exchange.
 *  EX_NOPERM -- You did not have sufficient permission to
 *      perform the operation.  This is not intended for
 *      file system problems, which should use NOINPUT or
 *      CANTCREAT, but rather for higher level permissions.
 */

#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 */

#endif /* !_SYSEXITS_H_ */

çıkıyor karşımıza…Uğraştım, Interneti altını üstüne getirdim ama istediğim kadar detaylı bilgileri bulamadım. Galiba tek sayfada görüntülenebilecek en detaylı liste bu oldu:

Exit Code İngilizce Türkçe
0 successful termination İşlem başarılı
1 Catchall for general errors 1 Genel hata kodu
2 Misuse of shell builtins 1 Hatalı seçenek ile kullanım ya da eksik argüman
64 command line usage error Kullanıcı hatası
65 data format error Yanlış argüman tipi
66 cannot open input Girdi (dosya ya da değer) açılamadı
67 addressee unknown Network adresi/url gibi şeyler bulunamayınca
68 host name unknown Aynı 67 gibi…
69 service unavailable Servis çalışmıyorsa/ulaşılamiyorsa
70 internal software error Tehlike durum :)
71 system error (e.g., can’t fork) Örneğin process’i fork yapamayınca
72 critical OS file missing İşletim sistemiyle ilgili dosya eksikse
73 can’t create (user) output file çıktı oluşturamayınca
74 input/output error I/O hatası
75 temp failure; user is invited to retry geçici hata, tekrar denenebilir
76 remote error in protocol Network ile ilgili durumlarda
77 permission denied Yetki dışında, izin yok!
78 configuration error Konfigurasyon hatası
126 Command invoked cannot execute 1 /dev/null
127 Command not found 1 $PATH de olmayan komut ya da yazım hatası
128 Invalid argument to exit 1 Örneğin: exit 3.14 gibi garip bir kod vermek.
128+n Fatal error signal “n” kill -9 $PPID bu, $? 128+9 döner.
130 Script terminated by Control-C kntrl + c basılınca, script’i durdurma

Bizler de, yazdığımız script’lerde, işlem sonuçlarında uygun olan kodu dönmeliyiz. Argüman alan bir script, argümansız çağırıldıysa, exit 2 ile bitirmeliyiz gibi. Boş zamanı olan arkdaşlar, man bash diyerek gelen muhteşem dökümanı ara ara okuyabilirler :) Ama ne yazıkki burada bile exit codes detayları yok.