12-04-2004
If you write a script, you can send input into it like this:
./somescript < inputfile
The script can accomplish the same thing internally by using:
exec < inputfile
After that line, the script's input is inputfile. It can do the same to output:
exec > somescript.log 2>&1
This send stderr and stdout combined into the file. There is more to it, but this is the basics.
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LEARN ABOUT DEBIAN
yexpand
YEXPAND(1) General Commands Manual YEXPAND(1)
NAME
yexpand - tool to expand environment variables in Nypatchy cradles
SYNOPSIS
yexpand inputfile [ outputfile ]
DESCRIPTION
yexpand is a very simple script to expand environment variables in a text file to their current values in the shell environment. It was
written to be used with nypatchy cradles. It is recommended you not try to use it for any other purposes (note BUGS below).
USAGE
yexpand takes inputfile as input, replaces all instances of shell variables (in the form $VARIABLE or ${VARIABLE}) with their current val-
ues in the environment, and saves the result to outputfile. Undefined variables are replaced with the empty string. If outputfile is not
given, the result is instead saved to the current directory as a file of the same name as inputfile. Thus an input file in the current
directory will be overwritten.
BUGS
This script is very simple-minded. Since it basically just echos its input file as a here-doc, it will attempt to perform all types of
shell substitution (command substitution, etc.) as well as variable substitution. Hence it is likely to fail on anything except the very
simplest text files.
Additionally, this script creates a temporary file. The file is created in the current directory, so there should not be security implica-
tions. However, any existing file named file.yexp (where file is the basename of inputfile) in the current directory will be overwritten
and then deleted.
SEE ALSO
fcasplit(1), nycheck(1), nydiff(1), nyindex(1), nylist(1), nymerge(1), nypatchy(1), nyshell(1), nysynopt(1), nytidy(1)
The reference manual for the Nypatchy suite of programs is available in compressed PostScript format at the following URL:
http://wwwasdoc.web.cern.ch/wwwasdoc/psdir/p5refman.ps.gz
AUTHOR
This manual page was written by Kevin McCarty <kmccarty@debian.org> for the Debian GNU/Linux system (but may be used by others). It is
licensed under the GNU General Public License, version 2 or later (at your choice).
COPYRIGHT
Copyright (C) Kevin B. McCarty, 2008.
Mar 12, 2008 YEXPAND(1)