Explanation of curl command

Configuration
1

Easy and simple questin about he curl commands found here:

sensor:
    # If this sensor returns anything other than 200, there's a problem with Plex!
    # Scans every 10 minutes
  - platform: command_line
    name: Plex HTTP Code
    command: curl -I http://192.168.1.X:32400/web/index.html 2>/dev/null | head -n 1 | cut -d$' ' -f2
    scan_interval: 600

I have tested it, and it works, no problem. But I have looked for a explanation for the parameters, and can’t realy find it.
Can anyone explain this? → 2>/dev/null | head -n 1 | cut -d$’ ’ -f2

2

2> redirects any error output. /dev/null says basically throw it away. I do not want to see that!
| is the pipe character used to do something to the output of the curl command.
head -n 1 uses the head command to just select the fist line of the output and discard anything else/
cut -d$’ ’ -f2 uses the cut command using the space character as a field delimiter. It outputs only the second field (everything between the first & second space characters).

So this question was about your Linux shell, the head command, and the cut command.

Sometimes knowing what to search for is half the battle :smiley:

2 Likes
3

Very good and informative answer, now I see how it works:)

1 Like
4

I was hoping it was clear. Sometimes when you know something so well it is difficult to explain to others,
I have been a UNIX administrator for many years.