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Full Discussion: bash & Ksh loop problem
Top Forums Shell Programming and Scripting bash & Ksh loop problem Post 302305219 by Corona688 on Wednesday 8th of April 2009 09:15:31 AM
Old 04-08-2009
Its a side-effect of using pipes. It forks off a new process, which has its own seperate variables, causing the value to be lost when the loop completes and the pipe closes. The values are only local to things behind the pipe, so try this:

Code:
ls | (  i=0
        while read I
        do
                i=$(($i + 1))
        done
        echo "total no of files : [$i]" )

You can avoid the pipe entirely by redirecting into a temp file:
Code:
ls > /tmp/$$-ls
i=0
while read I
do
        i=$((i+1))
done < /tmp/$$-ls
rm -f /tmp/$$-ls
echo "Total no of files: [$i]"

But there's probably security problems in depending on a temp file like that.

Also, you can count lines with the wc utility.
Code:
i=$(ls | wc -l)
echo $i

 

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LEARN ABOUT FREEBSD

atf-sh

ATF-SH(1)						    BSD General Commands Manual 						 ATF-SH(1)

NAME

     atf-sh [-s shell] -- interpreter for shell-based test programs

SYNOPSIS

     atf-sh script

DESCRIPTION

     atf-sh is an interpreter that runs the test program given in script after loading the atf-sh(3) library.

     atf-sh is not a real interpreter though: it is just a wrapper around the system-wide shell defined by ATF_SHELL.  atf-sh executes the inter-
     preter, loads the atf-sh(3) library and then runs the script.  You must consider atf-sh to be a POSIX shell by default and thus should not
     use any non-standard extensions.

     The following options are available:

     -s shell	  Specifies the shell to use instead of the value provided by ATF_SHELL.

ENVIRONMENT

     ATF_LIBEXECDIR    Overrides the builtin directory where atf-sh is located.  Should not be overridden other than for testing purposes.
     ATF_PKGDATADIR    Overrides the builtin directory where libatf-sh.subr is located.  Should not be overridden other than for testing purposes.
     ATF_SHELL	       Path to the system shell to be used in the generated scripts.  Scripts must not rely on this variable being set to select a
		       specific interpreter.

EXAMPLES

     Scripts using atf-sh(3) should start with:

	   #! /usr/bin/env atf-sh

     Alternatively, if you want to explicitly choose a shell interpreter, you cannot rely on env(1) to find atf-sh.  Instead, you have to hardcode
     the path to atf-sh in the script and then use the -s option afterwards as a single parameter:

	   #! /path/to/bin/atf-sh -s/bin/bash

ENVIRONMENT

     ATF_SHELL	  Path to the system shell to be used in the generated scripts.

SEE ALSO

     atf-sh(3)

BSD
								September 27, 2014							       BSD
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