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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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RBASH(1)						      General Commands Manual							  RBASH(1)

NAME
rbash - restricted bash, see bash(1) RESTRICTED SHELL
If bash is started with the name rbash, or the -r option is supplied at invocation, the shell becomes restricted. A restricted shell is used to set up an environment more controlled than the standard shell. It behaves identically to bash with the exception that the follow- ing are disallowed or not performed: o changing directories with cd o setting or unsetting the values of SHELL, PATH, ENV, or BASH_ENV o specifying command names containing / o specifying a file name containing a / as an argument to the . builtin command o specifying a filename containing a slash as an argument to the -p option to the hash builtin command o importing function definitions from the shell environment at startup o parsing the value of SHELLOPTS from the shell environment at startup o redirecting output using the >, >|, <>, >&, &>, and >> redirection operators o using the exec builtin command to replace the shell with another command o adding or deleting builtin commands with the -f and -d options to the enable builtin command o using the enable builtin command to enable disabled shell builtins o specifying the -p option to the command builtin command o turning off restricted mode with set +r or set +o restricted. These restrictions are enforced after any startup files are read. When a command that is found to be a shell script is executed, rbash turns off any restrictions in the shell spawned to execute the script. SEE ALSO
bash(1) GNU Bash-4.0 2004 Apr 20 RBASH(1)
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