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MKTEMP(1)		     General Commands Manual		       MKTEMP(1)

NAME
     mktemp -- make temporary file name (unique)

SYNOPSIS
     mktemp [-d] [-q] [-t prefix] [-u] template ...
     mktemp [-d] [-q] [-u] -t prefix

DESCRIPTION
     The  mktemp  utility  takes each of the given file name templates and over-
     writes a portion of it to create a file name.  This file name is unique and
     suitable for use by the application.  The template may  be  any  file  name
     with  some  number of `Xs' appended to it, for example /tmp/temp.XXXX.  The
     trailing `Xs' are replaced with the current process number and/or a  unique
     letter  combination.  The number of unique file names mktemp can return de-
     pends on the number of `Xs' provided; six `Xs' will result in mktemp  test-
     ing roughly 26 ** 6 combinations.

     If mktemp can successfully generate a unique file name, the file is created
     with mode 0600 (unless the -u flag is given) and the filename is printed to
     standard output.

     If  the  -t prefix option is given, mktemp will generate an template string
     based on the prefix and the TMPDIR environment variable if  set.	The  de-
     fault  location  if TMPDIR is not set is /tmp.  Care should be taken to en-
     sure that it is appropriate to use an environment variable potentially sup-
     plied by the user.

     Any number of temporary files may be created in a	single	invocation,  in-
     cluding one based on the internal template resulting from the -t flag.

     Mktemp  is  provided  to allow shell scripts to safely use temporary files.
     Traditionally, many shell scripts take the name of the program with the pid
     as a suffix and use that as a temporary file name.   This	kind  of  naming
     scheme  is predictable and the race condition it creates is easy for an at-
     tacker to win.  A safer, though still inferior, approach is to make a  tem-
     porary  directory	using the same naming scheme.  While this does allow one
     to guarantee that a temporary file will not be subverted, it still allows a
     simple denial of service attack.  For these reasons it  is  suggested  that
     mktemp be used instead.

OPTIONS
     The available options are as follows:

     -d      Make a directory instead of a file.

     -q      Fail  silently if an error occurs.  This is useful if a script does
	     not want error output to go to standard error.

     -t prefix
	     Generate a template (using the supplied prefix and TMPDIR	if  set)
	     to create a filename template.

     -u      Operate  in  "unsafe"  mode.  The temp file will be unlinked before
	     mktemp exits.  This is slightly better than mktemp(3) but still in-
	     troduces a race condition.  Use of this option is not encouraged.

DIAGNOSTICS
     The mktemp utility exits 0 on success, and 1 if an error occurs.

EXAMPLES
     The following sh(1) fragment illustrates a simple use of mktemp  where  the
     script should quit if it cannot get a safe temporary file.

	   tempfoo=`basename $0`
	   TMPFILE=`mktemp /tmp/${tempfoo}.XXXXXX` || exit 1
	   echo "program output" >> $TMPFILE

     To allow the use of $TMPDIR:

	   tempfoo=`basename $0`
	   TMPFILE=`mktemp -t ${tempfoo}` || exit 1
	   echo "program output" >> $TMPFILE

     In this case, we want the script to catch the error itself.

	   tempfoo=`basename $0`
	   TMPFILE=`mktemp -q /tmp/${tempfoo}.XXXXXX`
	   if [ $? -ne 0 ]; then
		   echo "$0: Can't create temp file, exiting..."
		   exit 1
	   fi

SEE ALSO
     mkdtemp(3), mkstemp(3), mktemp(3), environ(7)

HISTORY
     A	mktemp utility appeared in OpenBSD 2.1.  This implementation was written
     independently based  on  the  OpenBSD  man  page,	and  first  appeared  in
     FreeBSD 2.2.7.  This man page is taken from OpenBSD

Darwin 8.0.1			November 20, 1996		       MKTEMP(1)
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