Shell Programming and Scripting

Hi All

I ran a script in Linux.
In the script i have lines like

Code:

[ ! -f ${CM_ENV_FILE} ] && echo "Failed:       Missing ${CM_ENV_FILE} \n" && return 1
. ${CM_ENV_FILE}
Where CM_ENV_FILE = /data/ds/dpr_ebicm_uat//etl/cm3_0/entities/BBME/parameters/cm.env

But its taking this path
/data/ds/dpr_ebicm_uat/etl/cm3_0/scripts/shell//data/ds/dpr_ebicm_uat//etl/cm3_0/entities/BBME/parameters/cm.env
Due to which its throwing error as No such file or directory... whereas the file exists if only /data/ds/dpr_ebicm_uat//etl/cm3_0/entities/BBME/parameters/cm.env is considered.

Could you all please tell me why is this happening.
what does ". ${CM_ENV_FILE} " command mean in linux.

. <path/filename> will let the contents of that file be available to shell.

For e.g. you have a file "test.fn" (shown below) in the current directory. In it, you have written a function to add 2 numbers.

Code:

#! /bin/bash
add ()
{
    echo `expr $1 + $2`
}

Now, if you were to do this at the command prompt: ". test.fn", then the function "add" will be available for use at the command prompt.

You can do this at the command prompt: add 1 2
and the output will be 3

So the function add in test.fn file acts like a command. To unset this, you can say "unset add" and add will no longer be available at command prompt.

And try this line:
CM_ENV_FILE='/data/ds/dpr_ebicm_uat//etl/cm3_0/entities/BBME/parameters/cm.env'
(without spaces around '=' and the path/filename in sinqle quotes)