Script for sorting ~/.ssh/config by host alphabetically

ssh-config-sort.js

#!/usr/bin/env node

const fs = require('fs')
const os = require('os')
const readline = require('readline')

const home = `${os.homedir()}`
const configFile = `${home}/.ssh/config`

const lines = fs.readFileSync(configFile, 'utf-8').split('\n')
const blocks = []

let block = ''
for (const line of lines) {
  if (line.startsWith('Host ')) {
    if (block) {
      blocks.push(block)
      block = ''
    }
  }
  block += `${line}\n`
}

if (block) {
  blocks.push(block)
}

blocks.sort((a, b) => {
  const aHost = a.match(/^Host (.*)/m)[1]
  const bHost = b.match(/^Host (.*)/m)[1]
  return aHost.localeCompare(bHost)
})

const sortedConfig = blocks.join('')
console.log(sortedConfig)

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout
})

rl.question('Are you sure you want to write this output to ~/.ssh/config? (y/n): ', (answer) => {
  if (answer.toLowerCase() === 'y' || answer.toLowerCase() === 'yes') {
    fs.writeFileSync(configFile, sortedConfig)
    console.log('Config file written to ~/.ssh/config')

    fs.copyFileSync(configFile, `${configFile}.bak`)
    console.log('Backup file written to ~/.ssh/config.bak')
  } else {
    console.log('Cancelled by user')
  }

  rl.close()
})