Use the sed command to modify the kv configuration file in Linux

sed is a character stream editor under Unix, that is, a stream editor. It is line-oriented and processes in units of lines. At the same time, sed is non-interactive and once executed, it will process the entire file.

Daily background service configuration files are mostly in the form of key-value, such as ini files, toml files or some custom configuration files. When we need to write automated scripts to change the configuration files in some cases, we can use the shell's sed command to perform regular matching and quick modification, which is very simple and fast, reducing the tediousness of writing in a lot of "high-level languages". The following mainly lists two common configuration changes and command reference examples:

Configuration file test.conf for testing

$ cat test.conf 
max.connections = 100
test.log_path = "/tmp/test.log"
fsync=on

How to quote values

#!/bin/bash
CONF=test.conf
set_key_value() {
  local key=${1}
  local value=${2}
  if [ -n $value ]; then
    #echo $value
    local current=$(sed -n -e "s/^\($key = '\)\([^ ']*\)\(.*\)$/\2/p" $CONF) # value with single quotesif [ -n $current ];then
      echo "setting $CONF : $key = $value"
      value="$(echo "${value}" | sed 's|[&]|\\&|g')"
      sed -i "s|^[#]*[ ]*${key}\([ ]*\)=.*|${key} = '${value}'|" ${CONF}
    fi
  fi
}
set_key_value "max.connections" "1024"
set_key_value "test.log_path" "/data/logs/test.log"

Values ​​without quotes

CONF=test.conf
set_key_value() {
  local key=${1}
  local value=${2}
  if [ -n $value ]; then
    #echo $value
    local current=$(sed -n -e "s/^\($key = \)\([^ ']*\)\(.*\)$/\2/p" $CONF) # value without single quotesif [ -n $current ];then
      echo "setting $CONF : $key = $value"
      value="$(echo "${value}" | sed 's|[&]|\\&|g')"
      sed -i "s|^[#]*[ ]*${key}\([ ]*\)=.*|${key} = ${value}|" ${CONF}
    fi
  fi
}
set_key_value "fsync" "off"

Summarize

The above is what I introduced to you about how to modify the kv configuration file through the sed command under Linux. I hope it will be helpful to you. If you have any questions, please leave me a message and I will reply to you in time. I would also like to thank everyone for their support of the 123WORDPRESS.COM website!