1BASENAME(3)                Linux Programmer's Manual               BASENAME(3)
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NAME

6       basename, dirname - parse pathname components
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SYNOPSIS

9       #include <libgen.h>
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11       char *dirname(char *path);
12       char *basename(char *path);
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DESCRIPTION

15       Warning: there are two different functions basename(); see below.
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17       The functions dirname() and basename() break a null-terminated pathname
18       string into directory and filename  components.   In  the  usual  case,
19       dirname()  returns  the string up to, but not including, the final '/',
20       and basename() returns the component following the final '/'.  Trailing
21       '/' characters are not counted as part of the pathname.
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23       If  path  does  not  contain  a slash, dirname() returns the string "."
24       while basename() returns a copy of path.  If path is  the  string  "/",
25       then both dirname() and basename() return the string "/".  If path is a
26       null pointer or points to an empty  string,  then  both  dirname()  and
27       basename() return the string ".".
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29       Concatenating  the  string returned by dirname(), a "/", and the string
30       returned by basename() yields a complete pathname.
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32       Both dirname() and basename() may modify the contents of  path,  so  it
33       may be desirable to pass a copy when calling one of these functions.
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35       These  functions  may  return  pointers  to statically allocated memory
36       which may be overwritten by subsequent calls.  Alternatively, they  may
37       return  a  pointer to some part of path, so that the string referred to
38       by path should not be modified or freed until the pointer  returned  by
39       the function is no longer required.
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41       The following list of examples (taken from SUSv2) shows the strings re‐
42       turned by dirname() and basename() for different paths:
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44              path       dirname   basename
45              /usr/lib   /usr      lib
46              /usr/      /         usr
47              usr        .         usr
48              /          /         /
49              .          .         .
50              ..         .         ..
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RETURN VALUE

53       Both  dirname()  and  basename()  return  pointers  to  null-terminated
54       strings.  (Do not pass these pointers to free(3).)
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ATTRIBUTES

57       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
58       tributes(7).
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60       ┌────────────────────────────────────────────┬───────────────┬─────────┐
61Interface                                   Attribute     Value   
62       ├────────────────────────────────────────────┼───────────────┼─────────┤
63basename(), dirname()                       │ Thread safety │ MT-Safe │
64       └────────────────────────────────────────────┴───────────────┴─────────┘
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CONFORMING TO

67       POSIX.1-2001, POSIX.1-2008.
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NOTES

70       There are two different versions of basename() - the POSIX version  de‐
71       scribed above, and the GNU version, which one gets after
72
73               #define _GNU_SOURCE         /* See feature_test_macros(7) */
74               #include <string.h>
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76       The  GNU  version  never  modifies  its argument, and returns the empty
77       string when path has a trailing slash, and in particular also  when  it
78       is "/".  There is no GNU version of dirname().
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80       With glibc, one gets the POSIX version of basename() when <libgen.h> is
81       included, and the GNU version otherwise.
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BUGS

84       In the glibc implementation, the POSIX versions of these functions mod‐
85       ify  the  path  argument, and segfault when called with a static string
86       such as "/usr/".
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88       Before glibc 2.2.1, the glibc version of dirname()  did  not  correctly
89       handle pathnames with trailing '/' characters, and generated a segfault
90       if given a NULL argument.
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EXAMPLES

93       The following code snippet  demonstrates  the  use  of  basename()  and
94       dirname():
95           char *dirc, *basec, *bname, *dname;
96           char *path = "/etc/passwd";
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98           dirc = strdup(path);
99           basec = strdup(path);
100           dname = dirname(dirc);
101           bname = basename(basec);
102           printf("dirname=%s, basename=%s\n", dname, bname);
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SEE ALSO

105       basename(1), dirname(1)
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COLOPHON

108       This  page  is  part of release 5.12 of the Linux man-pages project.  A
109       description of the project, information about reporting bugs,  and  the
110       latest     version     of     this    page,    can    be    found    at
111       https://www.kernel.org/doc/man-pages/.
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115GNU                               2021-03-22                       BASENAME(3)
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