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Full Discussion: meaning of ${0%${0##*/}}
Operating Systems AIX meaning of ${0%${0##*/}} Post 302238841 by bakunin on Monday 22nd of September 2008 06:51:17 AM
Old 09-22-2008
Quote:
Originally Posted by nyelavarthy
. ${0%${0##*/}}Script2 or . ./Script2

Both do the same job. then why use this ". ${0%${0##*/}}Script2" instead of simply using ". ./Script2"?
In this case they expand to the same value, but that has not always to be the case. Suppose the following: you call your script not from the directory where it is stored but from somewhere else:

Code:
$ cd /some/dir
$ /some/other/dir/script
$ _

inside your script the "./" will expand to the PWD, which is not where the script is stored but where you have been when starting the script - "/some/dir" in the example, not "/some/other/dir". If you now execute

Code:
. ./script2

you will execute "/some/dir/script2" instead of "/some/other/dir/script2". Still $0 will contain "/some/other/dir/script" and subsequently the expansion will find script2 on its correct place.

As a rule of thumb: avoid relative paths like the plague in scripts. Always use absolute paths to make sure you end up where you suppose to end up.

I hope this helps

bakunin
 

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LEARN ABOUT LINUX

update-fonts-dir

update-fonts-dir(8)                                           System Manager's Manual                                          update-fonts-dir(8)

NAME

       update-fonts-dir - compile fonts.dir files

SYNOPSIS

       update-fonts-dir [OPTION] directory ...

DESCRIPTION

       update-fonts-dir creates a fonts.dir file in an X font directory by invoking mkfontdir(1x) with the appropriate arguments.  It is typically
       invoked only from the post-installation and post-removal scripts of a package containing fonts for the X Window System, but may be  invoked
       at  any  time  to  reconstruct  fonts.dir  files.   For  each directory, which is simply the last component of its path (such as '75dpi' or
       'misc'), update-fonts-dir will generate either /usr/lib/X11/fonts/directory/fonts.dir or /usr/share/fonts/X11/directory/fonts.dir from  the
       fonts.scale and font files found within it.

       This  enables  multiple packages to provide names for fonts in the same directory.  No font package actually provides the fonts.dir file in
       the X font directory itself, so there is no danger of overwriting one package's font names with those of another.

       For instance, the two packages  'xfonts-base'  (real)  and  'xfonts-nifty'  (hypothetical)  may  both  install  fonts  into  the  directory
       /usr/lib/X11/fonts/misc,  and  update-fonts-dir  will  ensure that the fonts.dir file in that directory contains information about the font
       files provided by both packages.

       The format of fonts.dir files is described in the mkfontdir(1x) manual page.

       An example of how to use update-fonts-dir in package maintainer scripts is provided in the Debian Policy Manual.

OPTIONS

       -h, --help displays a brief usage message and exits.

       -7, --x11r7-layout switches the font layout to the one introduced in X11R7: fonts in /usr/share/fonts/X11/directory (default is:  fonts  in
       /usr/lib/X11/fonts/directory)

OPERANDS

       update-fonts-dir  takes  one or more X font directory names to operate on as operands.  Only the final path component of the directory name
       should be specified; e.g.,
              update-fonts-dir 75dpi
       is correct, while 'update-fonts-dir /usr/X11R6/lib/X11/fonts/75dpi' and 'update-fonts-dir /usr/lib/X11/fonts/75dpi' are not.

ENVIRONMENT

       COLUMNS
              indicates the width of the terminal device in character cells.  This value is used for formatting diagnostic messages.  If not  set,
              the terminal is queried using stty(1) to determine its width.  If that fails, a value of '80' is assumed.

DIAGNOSTICS

   Errors
       usage error: one or more font directories must be provided
              update-fonts-dir was invoked without operands.  Supply one or more X font directory names to operate on.

       usage error: unrecognized option
              update-fonts-dir was invoked with an unrecognized option argument.  Use only the options documented in "OPTIONS", above.

       fatal error: path to X font directory must be used
              A directory name was supplied that was not an X font directory name.  Supply X font directory names only.

   Warnings
       warning: absolute path directory was provided
              Usage of absolute paths is deprecated.  Use only the final component of the X font directory name for directory.

       warning: directory does not exist or is not a directory
              The supplied directory was invalid.  update-fonts-dir skipped it.

EXIT STATUS

       0      update-fonts-dir ran successfully.

       1      update-fonts-dir experienced a fatal error; see the section on diagnostic messages above.

       2      update-fonts-dir was invoked with invalid arguments.

BUGS

       See  the  Debian  Bug  Tracking  System <http://bugs.debian.org/xfonts-utils>.  If you wish to report a bug in update-fonts-dir, please see
       /usr/share/doc/debian/bug-reporting.txt or the reportbug(1) command.

AUTHOR

       update-fonts-dir was written by Branden Robinson.

SEE ALSO

       mkfontdir(1x)

Debian Project                                                      2004-11-11                                                 update-fonts-dir(8)
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