Question

I would like to read a file into a script, line by line. Each line in the file is multiple values separated by a tab, I’d like to read each line into an array.

Typical bash “read file by line” example;

while read line
do
echo $line;
done < "myfile"

For me though, myfile looks like this (tab separated values);

value1 value2 value3
value4 value5 value6

On each iteration of the loop, I’d like each line to go into an array so I can

while read line into myArray
do
 echo myArray[0]
 echo myArray[1]
 echo myArray[2]
done < "myfile"

This would print the following on the first loop iteration;

value1
value2
value3

Then on the second iteration it would print

value4
value5
value6

Is this possible? The only way I can see is to write a small function to break out the values manually, is there built in support in bash for this?

Answer 1

You’re very close:

while IFS=$'\t' read -r -a myArray
do
 echo "${myArray[0]}"
 echo "${myArray[1]}"
 echo "${myArray[2]}"
done < myfile

(The -r tells read that \ isn’t special in the input data; the -a myArray tells it to split the input-line into words and store the results in myArray; and the IFS=$'\t' tells it to use only tabs to split words, instead of the regular Bash default of also allowing spaces to split words as well. Note that this approach will treat one or more tabs as the delimiter, so if any field is blank, later fields will be “shifted” into earlier positions in the array. Is that O.K.?)