Get terminal output after a command swift

Question

I run some commands in terminal with this code:

system(\"the command here\")

And after I want to know what is the result of running this c

Answer 1

system spawns a new process so you can’t capture its ouput. The equivalent that gives you a way to do this would be popen, which you could use like this:

import Darwin

let fp = popen("ping -c 4 localhost", "r")
var buf = Array(count: 128, repeatedValue: 0)

while fgets(&buf, CInt(buf.count), fp) != nil,
      let str = String.fromCString(buf) {
    print(str)
}

fclose(fp)

However, don’t do it this way. Use NSTask as Martin describes.

edit: based on your request to run multiple commands in parallel, here is some probably-unwise code:

import Darwin

let commands = [
    "tail /etc/hosts",
    "ping -c 2 localhost",
]

let fps = commands.map { popen($0, "r") }

var buf = Array(count: 128, repeatedValue: 0)

let results: [String] = fps.map { fp  in
    var result = ""
    while fgets(&buf, CInt(buf.count), fp) != nil,
          let str = String.fromCString(buf) {
        result += str
    }
    return result
}

fps.map { fclose($0) }

println("\n\n----\n\n".join(map(zip(commands,results)) { "\($0):\n\($1)" }))

(seriously, use NSTask)