Extract file contents into array using Bash

Question

How to extract a file content into array in Bash line by line. Each line is set to an element.

I've tried this:

declare -a array=(`cat "file name"`)

but it didn't work, it extracts the whole lines into [0] index element

Usually you won't need that. Can you tell why you want that anyway? — hek2mgl, Nov 30 '13 at 00:13

Håkon Hægland · Answer 1 · 2013-11-30T09:06:46.080

32

For bash version 4, you can use:

readarray -t array < file.txt

edited Nov 30 '13 at 09:06

answered Nov 30 '13 at 08:44

Håkon Hægland

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4

This is the sensible and efficient way to proceed in modern bash. Note that `readarray` is synonym of `mapfile`. – gniourf_gniourf Nov 30 '13 at 12:47
@Håkon Hægland I liked it because you helped me :-) thanks a lot – Learner Feb 11 '19 at 21:55

Junior Dussouillez · Accepted Answer · 2016-01-19T17:43:58.007

24

You can use a loop to read each line of your file and put it into the array

# Read the file in parameter and fill the array named "array"
getArray() {
    array=() # Create array
    while IFS= read -r line # Read a line
    do
        array+=("$line") # Append line to the array
    done < "$1"
}

getArray "file.txt"

How to use your array :

# Print the file (print each element of the array)
getArray "file.txt"
for e in "${array[@]}"
do
    echo "$e"
done

edited Jan 19 '16 at 17:43

answered Nov 30 '13 at 00:12

Junior Dussouillez

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I don't know why OP wants that. But however, this syntactically correct – hek2mgl Nov 30 '13 at 00:17

score 2 · Answer 3 · answered Nov 30 '13 at 07:27

2

This might work for you (Bash):

OIFS="$IFS"; IFS=$'\n'; array=($(<file)); IFS="$OIFS"

Copy $IFS, set $IFS to newline, slurp file into array and reset $IFS back again.

answered Nov 30 '13 at 07:27

potong

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This is subject to pathname expansion (and will discard empty lines)—don't use. – gniourf_gniourf Oct 15 '15 at 12:07

Extract file contents into array using Bash

3 Answers3