How to automatically change the password in the config?

Question

linux

Hello. There is a game server and I need to somehow automatically change one parameter in the config. For example, there is a variable rcon "faufI21FA"
faufI21FA - a password that needs to be changed randomly. Tell me the bash code so that I can specify the path to the txt file in which I need to write a random password in "". For example, I have this rcon.sh script in root, and the txt file is in /home/server/config.txt. So that I enter sh rcon.sh and the password faufI21FA is replaced with any other. I hope you understand me))
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You need a random pass and so that the new pass can also be replaced. I want to do it through cron so that every 30 minutes a variable in the
rcon "faufI21FA" config changes for example to rcon "VFyffa21" and this one to rcon "FGVsa24" and so on

Answer 1

#!/bin/bash
newpass=$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 10 | head -n 1)
sed -i.bak "s/^rcon .*$/rcon $newpass/" /path/to/myconfig.cfg

Answer 2

pass=$(/urandom tr -dc '[email protected]#^&)(*%KMNP-Za-hjk5-9mnp-z1-9' | head -c8)
sed -i 's/rcon. */rcon '${pass}'/g' /home/server/config.txt

Answer 3

Use sed Luke.
But it is better to replace the string with the password through a regular expression.
For example like this:

NEWPASSWORD=$(date +%s | sha256sum | base64 | head -c 10)
sed -i "s/rcon_password=.*/rcon_password=${NEWPASSWORD}/g" config.txt