Bash modify value in file with user input

Question

I have a config.py file containing

config['port'] = 11111

I want to edit this file. The tricky part is I want bash to take input from me and replace 11111 with the input i give.

Is that the only line in your config.py file? What do you mean by take input? Do you want it to prompt for input or would you like to enter your input as a parameter? What have you tried so far to accomplish this? — jesse_b, Dec 02 '17 at 15:02
I suggest that you instead modify the Python script to read the desired port from another standalone file. The idea of a bash script written just to interactively modify a Python script makes me cringe. It would make you cringe, too, if you had to maintain it. — Wildcard, Dec 02 '17 at 15:16
Also see Why is using a shell loop to process text considered bad practice? — Wildcard, Dec 02 '17 at 15:16

igal · Accepted Answer · 2017-12-02T15:15:34.233

3

How about this:

#!/bin/bash
# script.sh

# Prompt the user for input
echo "Choose a port number: "

# Read the input to a variable
read PORT

# Update the configuration file
sed -i "s/^\(config\['port'\] =\)\s\+[0-9]\+$/\1 ${PORT}/" config.py

If this is your input file:

# config.py
config['port'] = 123

And this is how you execute the command:

user@host:~$ bash script.sh
Choose a port number: 456

Then this is your updated file:

# config.py
config['port'] = 456

edited Dec 02 '17 at 15:15

answered Dec 02 '17 at 15:10

igal

9,886

You missed the part where igal explained how to run it ("your command") - by passing 456 as a parameter. – Jeff Schaller Dec 02 '17 at 15:15
@AyushMishra Updated to prompt the user for input. – igal Dec 02 '17 at 15:16

score 0 · Answer 2 · answered Dec 02 '17 at 15:34

0

new_port=12345
awk -v port="$new_port" '$0=="config['\'port\''] = 11111" { sub("11111",port); };
    { print; }' /path/to/file

answered Dec 02 '17 at 15:34

Hauke Laging

90,279

Bash modify value in file with user input

2 Answers2