Read strings from file and store them in multiple variables with bash

Question

I've been looking through a lot of posts here but none of them can completely solve this out.

I've got a configuration file (ie: default.conf) with several values in it:

id: 2
type: food
name: potato
quantity: 34

What I would like to achieve is to have a bash script to read the config file and assign every single value after the ":" (2, food, potato, 34...) to multiple variables for posterior use in that script.

Variables are meant to store singular strings. Store multiple strings in an array! — Inian
– Inian, Commented Jul 12, 2018 at 10:53
@ChandanKumar Use comments to ask for more information or suggest improvements. Avoid answering questions in comments. — John Kugelman
– John Kugelman, Commented Jul 12, 2018 at 11:48
Possible duplicate of Need bash shell script for reading name value pairs from a file and Code for parsing a key/value in in file from shell script — jww
– jww, Commented Jul 12, 2018 at 12:00

Hielke Walinga · Accepted Answer · 2018-07-12 11:49:13Z

1

I recommend using a associative array for this. This requires bash 4 or higher.

Loop over the file and use string manipulation from bash to assign the variables in your associative array.

declare -A conf_vars; while read line; do conf_vars[${line%:*}]=${line#*:}; done <default.conf

You can now use the variables by using e.g.: ${conf_vars[type]} which in your example gives food.

EDIT:
SO syntax coloring does not understand that in this case # does not indicate a comment. Just ignore it.

answered Jul 12, 2018 at 11:49

Hielke Walinga

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2 Comments

PesaThe Over a year ago

I recommend using ${line%%:*} in case the line had more colons in it.

Ruben Over a year ago

This one works perfect. I needed to use the double % as suggested by @PesaThe as I had a few more colons.

PesaThe · Accepted Answer · 2018-07-12 12:33:20Z

0

Using read with : delimiter:

declare -A vars
while IFS=: read -r lvalue rvalue; do
    vars[$lvalue]=${rvalue# }
done < data

${rvalue# } removes the extra space. If the space is required, use just ${rvalue}.

Output:

declare -p vars
declare -A vars=([id]="2" [quantity]="34" [name]="potato" [type]="food" )

edited Jul 12, 2018 at 12:33

answered Jul 12, 2018 at 11:57

PesaThe

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