Using variable in for loop in bash

Question

Simple question:

Fetch numbers(i) from a list of number; then use each of the number to do sth.

for i in list_of_number;do cat file|head -$(($i+1))|tail -1;done

This seems right but actually doesn't work. What's the problem here? thx

asf107 · Accepted Answer · 2012-01-03 16:14:24Z

1

Doing this will treat list_of_number as a string; I assume this is a file which contains a list of numbers that you want to loop over.

Try instead:

for i in `cat list_of_number`;do cat file|head -$(($i+1))|tail -1;done

answered Jan 3, 2012 at 16:14

asf107

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1 Comment

no worries, I make these types of mistakes all the time. Bash can be pretty unforgiving.