convert a line into array and print elements of array as variables in bash

Question

I am new in linux and I try reading a text file line by line. The lines are numbers. I want to add each line in an array and consider each number as a variable. My trial is as below:
Example of txt file:

1976   1   0  0.00    0.    68.    37.     0.   105.  0.14 0.02    4.3    1.1    2.2

What I need:
Putting each number in a variable. for example a = 1976 and b = 1 etc...
My code:

IFS=$'\n'
for next in `cat $filename`
do

line=$next

echo ${line[0]}
done

Result:

1976   1   0  0.00    0.    68.    37.     0.   105.  0.14 0.02    4.3    1.1    2.2

I found this command which results in the first number in the array 1976 but i do not know how to loop over the rest of the array echo $array | sed 's/^.* (".*"$)/\1/' — Omar Ali
– Omar Ali, Commented Jan 3, 2016 at 11:02
I tried this with changing the number in {print $0} to get the second and third field but it prints 1976 each time : while read -r line; do array=( $line ) echo $array | awk '{print $0}' done < read1.out — Omar Ali
– Omar Ali, Commented Jan 3, 2016 at 11:10

aleksanderzak · Accepted Answer · 2016-01-03 11:02:42Z

1

It's quite easy to store each value in an array. Here is an example:

while read -r -a line
do
 echo "${line[0]}"
 echo "${line[1]}"
 echo "${line[2]}"
done < $filename

-a line splits the input-line into words (white space seperated by default) and store the results in line array.

A snippet from read man:

-a Each name is an indexed array variable (see Arrays above).

You man not need the '-r' option. It basically make read to treat \ as nothing special in the input.

answered Jan 3, 2016 at 11:02

aleksanderzak

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4 Comments

aleksanderzak Over a year ago

Omar's code in the question suggested me that's what he's trying to achieve actually.

Omar Ali Over a year ago

thank you sir, the provided script works with removing the dollar sign from the file name

Omar Ali Over a year ago

Sir, Sorry I am still new. The fields are well extracted by your script but i do not know how to save them in variables for instance a=echo "${line[0]}" does not work

aleksanderzak Over a year ago

You can assign like so: a=${line[0]} , without echo. Still I'm not sure what you're trying to achieve and how helpful is that for you. That way you assign variables in a loop. You can still access them after the loop is executed, but if you do something like a=${line[0]} then a would contain a value for the last line read.

bogomips · Accepted Answer · 2016-01-03 15:38:36Z

0

# Add each line to Array
readarray -t aa < $filename
# Put each line into variables using Here String
for l in "${aa[@]}"; do
  read a b c <<< $l;     # Example using 3 variables, could be as many as on line
  # Do whatever has to be done with a, b, c, etc
done

answered Jan 3, 2016 at 15:38

bogomips

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