Put a proxy process in place of a program you want to run which will log all stdin/stdout/stderr in the pipe along with timestamps.
Kind of like tee but with timestamps and a bit easier to throw
all logs in one file and also into separate files.
Install the binary:
$ stack install
Copy the binary to the program you want to log:
$ cp $(which proclog) my-app
Make a config file under the same directory as my-app with the
extension .args: my-app.args
Put in the file (args are line separated)
--bin
/path/to/real/my-app
--log
/path/to/log/file.txt
Adjust as needed.
Now when you run my-app, it'll transparently log all
stdin/stdout/stderr to file.txt.
If desired, you can also add these
--stdin-file
/path/to/log/hls-stdin.txt
--stdout-file
/path/to/log/hls-stdout.txt
--stderr-file
/path/to/log/hls-stderr.txt
That'll also write to these files, while maintaining the mixed log above. Sometimes it's nice to switch between ways of viewing.