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Top Forums Shell Programming and Scripting Arithmetic operation in variable Post 302980833 by Corona688 on Friday 2nd of September 2016 05:42:02 PM
This question pops up an awful lot.

When you run shell commands in a pipe, they exist inside a different shell. This shell sums up the value perfectly and quits - leaving you in your original shell where the value was never changed.

Which end of the pipe is 'your' shell can vary from shell to shell. In KSH, you'd have gotten the total; I suspect you're running bash.

There's a few ways to deal with this and make it work in both.

Stuffing the entire program into the subshell with ( ) grouping braces:

Code:
git branch -r | (
        while read something
        do
                ...
        done 

        echo "total is $total"
)

Here-doc:

Code:
while read something
do
...
done <<EOF
$(git branch -r)
EOF

You could also use a temp file.
This User Gave Thanks to Corona688 For This Post:
 
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platform::shell(n)					       Tcl Bundled Packages						platform::shell(n)

__________________________________________________________________________________________________________________________________________________

NAME
platform::shell - System identification support code and utilities SYNOPSIS
package require platform::shell ?1.1.4? platform::shell::generic shell platform::shell::identify shell platform::shell::platform shell _________________________________________________________________ DESCRIPTION
The platform::shell package provides several utility commands useful for the identification of the architecture of a specific Tcl shell. This package allows the identification of the architecture of a specific Tcl shell different from the shell running the package. The only requirement is that the other shell (identified by its path), is actually executable on the current machine. While for most platform this means that the architecture of the interrogated shell is identical to the architecture of the running shell this is not generally true. A counter example are all platforms which have 32 and 64 bit variants and where a 64bit system is able to run 32bit code. For these running and interrogated shell may have different 32/64 bit settings and thus different identifiers. For applications like a code repository it is important to identify the architecture of the shell which will actually run the installed packages, versus the architecture of the shell running the repository software. COMMANDS
platform::shell::identify shell This command does the same identification as platform::identify, for the specified Tcl shell, in contrast to the running shell. platform::shell::generic shell This command does the same identification as platform::generic, for the specified Tcl shell, in contrast to the running shell. platform::shell::platform shell This command returns the contents of tcl_platform(platform) for the specified Tcl shell. KEYWORDS
operating system, cpu architecture, platform, architecture platform::shell 1.1.4 platform::shell(n)

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