Shell script : Want to show a few details in stdout & All details in log file

Question

Say, this is my shell script

echo "Show this on stdout and logfile"
wget -O .......  # "Only in logfile"
echo "Show this on stdout and logfile"
cp file1.txt     # "Only in logfile"

So, I want to store the whole script output in a log file (say "complete-output.log")

And on my stdout --- I want to show only some cherry-picked items (Ex. some echo messages)

---

I used named pipes,

# Set up a named pipe for logging
npipe=logpipe
mknod $npipe p

# Log all output to a log for error checking
sudo tee <$npipe /var/log/complete-output.log &
exec 1>$npipe 2>&1

# Deleting named pipe on script EXIT
trap 'rm -f $npipe' EXIT

So, I am getting complete output on both (In file, as well as stdout)

---

But, I do not want stdout to be so verbose.. only want to show a few things there !

What is the correct way to do so ? Thanks in advance !

Answer 1

Can this achieve what you wanted ?

#!/usr/bin/env bash

echo2(){
    echo "$@"
    echo "$@" > /dev/tty
}

exec > /var/log/complete-output.log 2>&1

echo2 "Show this on stdout and logfile"
echo wget -O .......  # "Only in logfile"
echo2 "Show this on stdout and logfile"
echo cp file1.txt     # "Only in logfile"

Run it with

$ bash test.sh
Show this on stdout and logfile
Show this on stdout and logfile
$ cat /var/log/complete-output.log
Show this on stdout and logfile
wget -O .......
Show this on stdout and logfile
cp file1.txt