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Top Forums Shell Programming and Scripting How to empty a file(already created) Post 302125210 by porter on Wednesday 4th of July 2007 11:55:07 AM
Old 07-04-2007
Quote:
Originally Posted by laknar
i need to empty a file which is already existing.
cat </dev/null >file
 

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ShellQuote(3pm) 					User Contributed Perl Documentation					   ShellQuote(3pm)

NAME
String::ShellQuote - quote strings for passing through the shell SYNOPSIS
$string = shell_quote @list; $string = shell_quote_best_effort @list; $string = shell_comment_quote $string; DESCRIPTION
This module contains some functions which are useful for quoting strings which are going to pass through the shell or a shell-like object. shell_quote [string]... shell_quote quotes strings so they can be passed through the shell. Each string is quoted so that the shell will pass it along as a single argument and without further interpretation. If no strings are given an empty string is returned. If any string can't be safely quoted shell_quote will croak. shell_quote_best_effort [string]... This is like shell_quote, excpet if the string can't be safely quoted it does the best it can and returns the result, instead of dying. shell_comment_quote [string] shell_comment_quote quotes the string so that it can safely be included in a shell-style comment (the current algorithm is that a sharp character is placed after any newlines in the string). This routine might be changed to accept multiple string arguments in the future. I haven't done this yet because I'm not sure if the strings should be joined with blanks ($") or nothing ($,). Cast your vote today! Be sure to justify your answer. EXAMPLES
$cmd = 'fuser 2>/dev/null ' . shell_quote @files; @pids = split ' ', `$cmd`; print CFG "# Configured by: ", shell_comment_quote($ENV{LOGNAME}), " "; BUGS
Only Bourne shell quoting is supported. I'd like to add other shells (particularly cmd.exe), but I'm not familiar with them. It would be a big help if somebody supplied the details. AUTHOR
Roderick Schertler <roderick@argon.org> SEE ALSO
perl(1). perl v5.8.4 2005-05-03 ShellQuote(3pm)
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