如果我将输出通过管道传输到 tee，则无法“继续”

Question

I have a bash script that does pretty-much what I want using the following structure:

for x in 1 2 3
do
  {
  [[ $x -ne 2 ]] || continue
  echo $x
  } &>> foo.log
done

I need to change it so the output goes both to the terminal and the log file. This, however, doesn't work:

for x in 1 2 3
do
  {
  [[ $x -ne 2 ]] || continue
  echo $x
  } 2>&1 | tee -a foo.log
done

It looks like, by creating a process, the pipe prevents me from using continue .

Of course, I could rewrite the logic of my script without continue , but before I jump into that, I'm wondering if I'm missing a more straightforward way to achieve what I want.

Answer 1

You could redirect the output to a process substitution.

for x in 1 2 3
do
  {
  [[ $x -ne 2 ]] || continue
  echo $x
  } 2>&1 > >(tee -a foo.log)
done |
# I suggest to do pipe the output to ex. `cat`, so that the output 
# of process substitution will be synchronized with rest of the script
cat

But why not just redirect the output of the whole loop?

for x in 1 2 3; do
  [[ $x -ne 2 ]] || continue
  echo $x
done 2>&1 | tee -a foo.log

You could exit from the subprocess. If you would do that, I would suggest replacing { } with ( ) just to be safe if you one day decide to remove the tee .

for x in 1 2 3
do
  {
  [[ $x -ne 2 ]] || exit
  echo $x
  } 2>&1 | tee -a foo.log
done