how can I check if child_process can run a command?
'echo' is a valid command that can be run in a terminal, but 'echoes' is not one. For example, if I do this
const cp = require('child_process')
cp.exec('echo hello')
it will work.
If I do this, though
const cp = require('child_process')
cp.exec('echoes hello') //notice how it is echoes instead of echo
it will just error, but maybe the user has a program that adds 'echoes' to a terminal, and in that case, it would be able to run, but if it errors it will just exit out of the process and I won't be able to check if it works.
Is there any way to do this? Thank you so much in advance!
You have to manually loop through dirs in $PATH env & perform look up on those directory.
eg: $PATH is set to /bin:/usr/local/bin then you have to perform
fs.access('/bin/' + command, fs.constants.X_OK)
and
fs.access('/usr/local/bin/' + command, fs.constants.X_OK)
solution would look like this.
const { constants: fsconsts } = require('fs')
const fs = require('fs/promises')
const path = require('path')
const paths = process.env.PATH.split(':')
async function isExecutable(command) {
const cases = []
for (const p of paths) {
const bin = path.join(p, command)
cases.push(fs.access(bin, fsconsts.X_OK)) // X_OK is bit flag which makes sure file is executable
}
await Promise.any(cases)
return command
}
const found = (bin) => console.log('found', bin)
const notfound = (errors) => {
console.log('not found or not executable')
// console.error(errors)
}
// passes
isExecutable('echo').then(found).catch(notfound)
isExecutable('node').then(found).catch(notfound)
// fails
isExecutable('shhhhhh').then(found).catch(notfound)
isExecutable('echoes').then(found).catch(notfound)
NOTE: I think my solution works only on *nix based OSs