Setting Integer Variables in Bash

[Tim McDaniel]

On Thu, 29 Jan 2009, whitewall <thewhitewall@live.co.uk> wrote:
> The text below is from a text file.  If I type the commands
> line-by-line in the bash then the commands work as expected.  If I
> save the commands in a text file and call the script I get the error
> message:
> ': not a valid identifier2: declare: 'Red
> ': not a valid identifier3: declare: 'Green

Two error messages.

> #! /cygdrive/c/cygwin/bin/bash
> declare -i Red
> declare -i Green
> Red=10
> Green=$Red+1
> echo $Green
> exit 0

You have a carriage return at the end of each line.  bash does NOT
consider carriage return to be whitespace, dammit, so it is considered
normal characters.  So it things, for example, that you're declaring a
variable named "Red\r", a four-character name, and it just doesn't
allow carriage return in the variable name.

The key to recognizing the situation is to see
     ': not a valid identifier2: declare: 'Red
and recognize that there's a carriage return in the middle of the
message.  The opening ' is just before Red.  Its matching closing ' is
shown as the start of the line -- because carriage return causes the
output display to return to the start of line.

So
- by default, created files in UNIX file format, not native Windows.
- strip out the carriage returns from your existing script

-- 
Tim McDaniel, tmcd@panix.com

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