4

When I press Ctrl+T while some program is running in a terminal, I get some extra output, e.g.:

$ ping -q -c 100 google.com
PING google.com (172.217.16.46): 56 data bytes
load: 2.39  cmd: ping 5374 running 0.00u 0.00s
2/2 packets received (100.0%) 33.914 min / 34.169 avg / 34.423 max
...

Where does the output come from? Are there any other useful shortcuts that can be handled by a terminal?

  • I believe this is a BSD (only?) thing. Ctrl+T requests status info from the terminal driver. – Kusalananda Oct 20 at 21:02
  • 1
    Searching for Ctrl-T shows this. – Thomas Dickey Oct 20 at 22:25
  • Ctrl-T goes back to at least TOPS-20 on the DESCSYSTEM-20. – Johan Myréen Oct 21 at 6:32
10

On some Unix-style systems (BSDs and macOS), CtrlT sends SIGINFO to the running process. Some commands handle this directly; otherwise, it’s handled by the kernel, and that’s what produces the output you’re seeing.

SIGINFO on GNU Linux (Arch Linux) missing has more on the topic.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.