Showing only the uptime from uptime [unix]

Question

I'd like to trim the output from uptime

20:10  up 23 days,  3:28, 3 users, load averages: 3.84 1.06 0.64

so that it just shows:

23 days

I've tried using sed, but I'm not sure it's the right tool for the job, and don't have much experience using it.

How can I achieve the output I want?

Answer 1

Consider using cut.

  uptime | tr "," " " | cut -f6-8 -d" "

seems to work on my MacBook. Here I've also used tr to kill an extraneous ",". There is a bit of an issue with different formats for short and long uptimes.

---

A possible sed solution:

uptime | sed 's/.*up \([^,]*\), .*/\1/'

which doesn't rely on the string "days" appearing in the output of uptime.

Answer 2

uptime | sed -E 's/^.+([0-9]+ days).+$/\1/'

Answer 3

you can just use the shell without any external tools

$ var="20:10  up 23 days,  3:28, 3 users, load averages: 3.84 1.06 0.64"
$ var=${var/#*up}
$ echo ${var%%,*}
23 days