Substituting variables from external files

oneillc9 · #1 (**permalink**) 07-31-2008

Hi All,

I have the following problem:

1. I have a file containing a line:
a,b,d,${d},e,f

2. From within a script I grep the file for '^a,' to get the line
3. I obtain the fourth field as follows:
Field4="$( print -r $fileEntry | cut -d, -f4 )"
4. The script exports variables at the beginning including ${d}

How do I get ${Field4} to contain the substituted variable ${d} instead of the literal '${d}'

I hope this is clear, I am happy to explain anything if I am talking jibberish.

Thanks in advance.

Chris

Franklin52 · #2 (**permalink**) 07-31-2008

Use eval to get the value of ${d}:

Code:

d=100
Field4="$( print -r $fileEntry | cut -d, -f4 )"  # Field4 is literal ${d}
eval "eval_var=$Field4"  # now $eval_var holds the value of ${d}
echo ${eval_var}    # should print 100

Regards

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