basename(1)basename(1)NAME
basename, dirname - Returns the base file name or directory portion of
a path name
SYNOPSISbasename string [suffix]
dirname string
STANDARDS
Interfaces documented on this reference page conform to industry stan‐
dards as follows:
basename: XCU5.0
dirname: XCU5.0
Refer to the standards(5) reference page for more information about
industry standards and associated tags.
OPTIONS
None
OPERANDS
A string to be evaluated. This string may be empty. A file name suf‐
fix to be deleted if found. This operand applies to the basename com‐
mand only, and is optional.
DESCRIPTION
The basename command reads the string specified on the command line,
deletes the portion from the beginning to the last / (slash), and
writes the base file name to standard output. If suffix is specified
on the command line and suffix appears in string, the string is
returned with the suffix removed.
The dirname command reads the string specified on the command line,
deletes from the last / (slash) to the end of the line, and writes the
remaining path name to standard output.
[Tru64 UNIX] The basename and dirname commands are generally used
inside command substitutions within a shell procedure to specify an
output file name that is some variation of a specified input file name.
For more information, see the csh(1), ksh(1), and sh(1b) or sh(1p) ref‐
erence pages.
The following table demonstrates the processing applied to characters
with particular meanings by the basename and dirname commands.
──────────────────────────────
basename dirname
string Result Result
──────────────────────────────
/ / /
// / /
/a/b b /a
//a//b// b //a
<null> err msg err msg
a a .
"" .
/a a /
/a/b b /a
a/b b a
──────────────────────────────
NOTES
It is not an error if suffix is not a part of string.
EXAMPLES
To display the base file name of a shell variable, enter: basename
$WORKFILE
This displays the base file name of the value assigned to the
WORKFILE shell variable. If WORKFILE is set to /u/gabe/pro‐
gram.c, then program.c is displayed. To construct, in a shell
script, a file name that is the same as another file name,
except for its suffix, enter the following command, using grave
accents: OFILE=`basename $1 .c`.o
This assigns to OFILE the value of the first positional parame‐
ter ($1), but with its suffix changed to $1 is /u/jim/program.c,
then OFILE becomes program.o. Because program.o is only a base
file name, it identifies a file in the current directory.
The grave accents perform command substitution. To construct
the name of a file located in the same directory as another,
enter the following command, using grave accents: AOUT‐
FILE=`dirname $TEXTFILE`/a.out
This sets the AOUTFILE shell variable to the name of an a.out
file that is in the same directory as TEXTFILE. If TEXTFILE is
/u/fran/prog.c, then the value of dirname $TEXTFILE is /u/fran
and AOUTFILE becomes /u/fran/a.out.
ENVIRONMENT VARIABLES
The following environment variables affect the execution of basename
and dirname: Provides a default value for the internationalization
variables that are unset or null. If LANG is unset or null, the corre‐
sponding value from the default locale is used. If any of the interna‐
tionalization variables contain an invalid setting, the utility behaves
as if none of the variables had been defined. If set to a non-empty
string value, overrides the values of all the other internationaliza‐
tion variables. Determines the locale for the interpretation of
sequences of bytes of text data as characters (for example, single-byte
as opposed to multibyte characters in arguments). Determines the
locale for the format and contents of diagnostic messages written to
standard error. Determines the location of message catalogues for the
processing of LC_MESSAGES.
SEE ALSO
Commands: csh(1), ksh(1), Bourne shell sh(1b), POSIX shell sh(1p)
Standards: standards(5)basename(1)
