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OpenSolaris 2009.06 - man page for mktemp (opensolaris section 1)

mktemp(1)				  User Commands 				mktemp(1)

       mktemp - make temporary filename

       mktemp [-dtqu] [-p directory] [template]

       The  mktemp  utility  makes  a  temporary filename. To do this, mktemp takes the specified
       filename template and overwrites a portion of it to create a unique  filename.  See  OPER-

       The template is passed to mkdtemp(3C) for directories or mkstemp(3C) for ordinary files.

       If  mktemp can successfully generate a unique filename, the file (or directory) is created
       with file permissions such that it is only readable and writable by its owner (unless  the
       -u flag is given) and the filename is printed to standard output.

       mktemp  allows  shell  scripts  to  safely  use temporary files. Traditionally, many shell
       scripts take the name of the program with the PID as a suffix and used that as a temporary
       filename.  This	kind of naming scheme is predictable and the race condition it creates is
       easy for an attacker to win. A safer, though still inferior approach is to make	a  tempo-
       rary  directory	using the same naming scheme. While this guarantees that a temporary file
       is not subverted, it still allows a simple denial of service attack. Use mktemp instead.

       The following options are supported:

       -d	       Make a directory instead of a file.

       -p directory    Use the specified directory as a  prefix  when  generating  the	temporary
		       filename.  The  directory  is  overridden by the user's TMPDIR environment
		       variable if it is set. This option implies the -t flag.

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

       -t	       Generate  a path rooted in a temporary directory. This directory is chosen
		       as follows: If the user's TMPDIR environment variable is set,  the  direc-
		       tory  contained	therein  is used. Otherwise, if the -p flag was given the
		       specified directory is used. If none of the above apply, /tmp is used.  In
		       this mode, the template (if specified) should be a directory component (as
		       opposed to a full path) and thus should not contain any forward slashes.

       -u	       Operate in unsafe mode. The temp file is  unlinked  before  mktemp  exits.
		       This  is slightly better than mktemp(3C), but still introduces a race con-
		       dition. Use of this option is discouraged.

       The following operands are supported:

       template    template can be any filename with one or more Xs appended to it,  for  example

		   If  template is not specified, a default of tmp.XXXXXX is used and the -t flag
		   is implied.

       Example 1 Using mktemp

       The following example illustrates a simple use of mktemp in a sh(1) script. In this  exam-
       ple, the script quits if it cannot get a safe temporary file.

	 TMPFILE=`mktemp /tmp/example.XXXXXX`
	 if [ -z "$TMPFILE" ]; then exit 1; fi
	 echo "program output" >> $TMPFILE

       Example 2 Using mktemp to Support TMPDIR

       The following example uses mktemp to support for a user's TMPDIR environment variable:

	 TMPFILE=`mktemp -t example.XXXXXX`
	 if [ -z "$TMPFILE" ]; then exit 1; fi
	 echo "program output" >> $TMPFILE

       Example 3 Using mktemp Without Specifying the Name of the Temporary File

       The  following  example	uses mktemp without specifying the name of the temporary file. In
       this case the -t flag is implied.

	 if [ -z "$TMPFILE" ]; then exit 1; fi
	 echo "program output" >> $TMPFILE

       Example 4 Using mktemp with a Default Temporary Directory Other than /tmp

       The following example creates the temporary file in /extra/tmp unless  the  user's  TMPDIR
       environment variable specifies otherwise:

	 TMPFILE=`mktemp -p /extra/tmp example.XXXXX`
	 if [ -z "$TMPFILE" ]; then exit 1; fi
	 echo "program output" >> $TMPFILE

       Example 5 Using mktemp to Remove a File

       The  following  example	attempts to create two temporary files. If creation of the second
       temporary file fails, mktemp removes the first file before exiting:

	 TMP1=`mktemp -t example.1.XXXXXX`
	 if [ -z "$TMP1" ]; then exit 1; fi
	 TMP2=`mktemp -t example.2.XXXXXX`
	 if [ -z "$TMP2" ]; then
		 rm -f $TMP1
		 exit 1

       Example 6 Using mktemp

       The following example does not exit if mktemp is unable to create the file. That  part  of
       the script has been protected.

	 TMPFILE=`mktemp -q -t example.XXXXXX`
	 if [ ! -z "$TMPFILE" ]
		 # Safe to use $TMPFILE in this block
		 echo data > $TMPFILE
		 rm -f $TMPFILE

       See  environ(5)	for  descriptions  of the following environment variables that affect the
       execution of mktemp with the -t option: TMPDIR.

       The following exit values are returned:

       0    Successful completion.

       1    An error occurred.

       See attributes(5) for descriptions of the following attributes:

       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       |Availability		     |SUNWcsu			   |
       |Interface Stability	     |Committed 		   |

       sh(1), mkdtemp(3C), mkstemp(3C), attributes(5), environ(5)

       The mktemp utility appeared in OpenBSD 2.1. The Solaris implementation uses only  as  many
       `Xs' as are significant for mktemp(3C) and mkstemp(3C).

SunOS 5.11				   10 Jan 2008					mktemp(1)

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