bash - count and output lines from command

Question

I'm writing a small script that needs to run a program that outputs multiple lines, and then display the count of those lines. The program, however, can take several seconds to run and I would rather not run it twice, once for the output and another for the count.

I can do it running the program twice:

#!/bin/bash
count=$(program-command | wc -l)
program-command
printf "$count lines"

Is there a way to get the count and output while only running the program once? This output has formatting, so ideally that formatting (colors) would be preserved.

Answer 1

Use tee and process substitution:

program-command | tee >(wc -l)

To preserve color, prefix the command with script -q /dev/null as per this answer:

script -q /dev/null program-command | tee >(wc -l)

Answer 2

You could use awk:

program-command | awk '{print $0; count++} END {print count}'