Need bash shell script for reading name value pairs from a file

Question

I have a file like

name1=value1
name2=value2

I need to read this file using shell script and set variables

$name1=value1
$name2=value2

Please provide a script that can do this.

I tried the first answer below, i.e. sourcing the properties file but I'm getting a problem if the value contains spaces. It gets interpreted as a new command after the space. How can I get it to work in the presence of spaces?

Related: https://stackoverflow.com/questions/15365871/code-for-parsing-a-key-value-in-in-file-from-shell-script — tripleee, Oct 10 '17 at 09:37

score 35 · Answer 1 · answered Feb 14 '11 at 09:41

35

If all lines in the input file are of this format, then simply sourcing it will set the variables:

source nameOfFileWithKeyValuePairs

or

. nameOfFileWithKeyValuePairs

answered Feb 14 '11 at 09:41

Joachim Sauer

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Hey, I'm getting problem if the value contains spaces. It gets interpreted as a new command after the space. Please tell how to get it working in the presence of spaces. – Walking Corpse Feb 15 '11 at 11:35
2

I have dots in my keys (e.g. `data.dir=/path/to/data/dir`). It gives errors such as `Command not found` or `No such file or directory` depending on the value. Any idea how to fix this issue? – Isaac Sep 06 '13 at 23:33
As noted elsewhere here, 'source' works for many cases but a) may have security implications, and b) will not function for values that have for example "$" in them. – NuSkooler Sep 19 '18 at 18:34
1

Why you should not source file (big security risk) - https://unix.stackexchange.com/a/433245/364638 – Shishir Gupta Jun 16 '21 at 07:56

score 21 · Accepted Answer · edited Nov 08 '18 at 10:43

21

Use:

while read -r line; do declare  "$line"; done <file

edited Nov 08 '18 at 10:43

codesalsa

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answered Feb 14 '11 at 09:49

kurumi

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Ok I figured this works while read -r line; do declare "$line"; done – Walking Corpse Feb 15 '11 at 11:39
@kurumi, please consider editing this to add quotes. It *is* faulty without them. – Charles Duffy May 21 '17 at 21:29

score 19 · Answer 3 · answered Sep 05 '14 at 05:09

19

Sourcing the file using . or source has the problem that you can also put commands in there that are executed. If the input is not absolutely trusted, that's a problem (hello rm -rf /).

You can use read to read key value pairs like this if there's only a limited known amount of keys:

read_properties()
{
  file="$1"
  while IFS="=" read -r key value; do
    case "$key" in
      "name1") name1="$value" ;;
      "name2") name2="$value" ;;
    esac
  done < "$file"
}

answered Sep 05 '14 at 05:09

robinst

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This is great as it matches keys with dots: `"key.subkey") name1="$value" ;;` – Steve Eynon Mar 31 '16 at 13:42
1

Note that your property file needs a trailing new line `\n` character on the last line or it won't get read. – Steve Eynon Jun 20 '16 at 16:05

score 17 · Answer 4 · edited Sep 05 '18 at 11:33

17

if your file location is /location/to/file and the key is mykey:

grep mykey $"/location/to/file" | awk -F= '{print $2}'

edited Sep 05 '18 at 11:33

consuela

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answered Sep 05 '18 at 11:14

Alex Stoliar

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Daniel Alder · Answer 5 · 2015-01-13T10:31:48.777

7

Improved version of @robinst

read_properties()
{
  file="$1"
  while IFS="=" read -r key value; do
    case "$key" in
      '#'*) ;;
      *)
        eval "$key=\"$value\""
    esac
  done < "$file"
}

Changes:

Dynamic key mapping instead of static
Supports (skips) comment lines

A nice one is also the solution of @kurumi, but it isn't supported in busybox

And here a completely different variant:

eval "`sed -r -e "s/'/'\\"'\\"'/g" -e "s/^(.+)=(.+)\$/\1='\2'/" $filename`"

(i tried to do best with escaping, but I'm not sure if that's enough)

edited Jan 13 '15 at 10:31

answered Jan 13 '15 at 09:26

Daniel Alder

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This is a good one, but it does not read the last line. How to fix? – Andrew Apr 03 '20 at 02:32
@Andrew good point, didn't know about this. Seems to be something in `read -r key value` which I cannot even reproduce without the loop. Any help out there? – Daniel Alder Apr 03 '20 at 13:14

score 6 · Answer 6 · answered Feb 14 '11 at 09:45

6

suppose the name of your file is some.properties

#!/bin/sh
# Sample shell script to read and act on properties

# source the properties:
. some.properties

# Then reference then:
echo "name1 is $name1 and name2 is $name2"

answered Feb 14 '11 at 09:45

Clyde Lobo

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While true, this should come with the big blinking red warning label that reads "EVAL! EVAL! YOU'RE USING EVAL HERE!" unless there is absolute undoubted control over the input file. – Ulrich Schwarz Feb 14 '11 at 09:47
Is there any difference if I source as .some.properties and . ./some.properties – Bharthan Jul 19 '16 at 16:38

Koichi Nakashima · Answer 7 · 2021-08-26T00:08:05.833

Use shdotenv

dotenv support for shell and POSIX-compliant .env syntax specification https://github.com/ko1nksm/shdotenv

Usage: shdotenv [OPTION]... [--] [COMMAND [ARG]...]

  -d, --dialect DIALECT  Specify the .env dialect [default: posix]
                           (posix, ruby, node, python, php, go, rust, docker)
  -s, --shell SHELL      Output in the specified shell format [default: posix]
                           (posix, fish)
  -e, --env ENV_PATH     Location of the .env file [default: .env]
                           Multiple -e options are allowed
  -o, --overload         Overload predefined environment variables
  -n, --noexport         Do not export keys without export prefix
  -g, --grep PATTERN     Output only those that match the regexp pattern
  -k, --keyonly          Output only variable names
  -q, --quiet            Suppress all output
  -v, --version          Show the version and exit
  -h, --help             Show this message and exit

Load the .env file into your shell script.

eval "$(shdotenv [OPTION]...)"

Rajesh Kumar · Answer 8 · 2023-07-16T16:27:51.740

0

    filename="config.properties"

# Read the file and extract key-value pairs
while IFS='=' read -r key value; do
    # Skip empty lines or lines starting with #
    if [[ -z $key || $key == \#* ]]; then
        continue
    fi

    # Trim leading/trailing whitespace from key
    key=$(echo "$key" | awk '{gsub(/^ +| +$/,"")} {print $0}')

    # Extract the value after the first equals sign
    value="${line#*=}"
    
    # Assign value to the variable dynamically
    declare "$key"="$value"
done < "$filename"

# Print the variables
echo "key1: $key1"
echo "key2: $key2"
echo "key3: $key3"

edited Jul 16 '23 at 16:27

answered Jul 16 '23 at 16:19

Rajesh Kumar

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As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Jul 20 '23 at 00:11

Need bash shell script for reading name value pairs from a file

8 Answers8

Use shdotenv

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