How to log a output(regular or error) of a unix program into a file

Question

logging a output(regular or error) of a unix program into a file.

Answer 1

start it with

./program > file.log 2>&1

this will redirect stdout and stderr to file.log

Answer 2

Redirection like the above answer is very standard, but sometimes you really want to capture everything in a session. For that you can use the 'script' command.

$ script /path/to/output_file
[starts a subshell]
$ ./program
$ exit
$ cat /path/to/output_file

The advantage of script is you don't need to worry about shell semantics and knowing which shell you're running etc.. The disadvantage is that it really does capture everything that makes it to your terminal, including control codes, delete keys, etc...