How to truncate the middle of long command output

Use a command group { head -n 3; echo '[…]'; tail -n 5; } to snip print the first few and last few lines.

If I’m running a command with lots of output, I can use head(1) to get the first few lines, or tail(1) to get the last few lines. What if I want to get some lines from the beginning and from the end, but truncate the middle?

In bash, I can use command grouping, which runs all the commands inside curly braces as a single unit. Here’s an example:

$ tailscale exit-node list | { head -n 3; echo ' […]'; tail -n 5; }

 IP                  HOSTNAME                         COUNTRY            CITY                   STATUS
 100.111.189.27      al-tia-wg-003.mullvad.ts.net     Albania            Tirana                 -
 […]
 100.93.242.75       ua-iev-wg-001.mullvad.ts.net     Ukraine            Kyiv                   -

# To view the complete list of exit nodes for a country, use `tailscale exit-node list --filter=` followed by the country name.
# To use an exit node, use `tailscale set --exit-node=` followed by the hostname or IP.
# To have Tailscale suggest an exit node, use `tailscale exit-node suggest`.