Package: apt
Version: 1.8.0
File: /usr/bin/apt-cache
In Unix/Linux we have STDOUT and STDERR. Please just use these two,
and don't invent "smarter ways."
Really really bad and this will come back to bite you one day:
You have a kind of message that is only shown if the user is on a tty.
You don't user the industry standard of sending it to STDERR,
You instead just hide it... if the user apparently isn't using a TTY.
One can't even pipe the output of your program to any other program,
expecting messages to go to STDERR. The message just disappears!
$ apt-cache show twitter-bootstrap
N: Can't select candidate version from package twitter-bootstrap as it has no
candidate
N: Can't select versions from package 'twitter-bootstrap' as it is purely
virtual
N: No packages found
$ apt-cache show twitter-bootstrap 2>&1|wc
0 0 0
In fact I can think of no other program in the entire history of Unix
that has decided to do that.
If the user doesn't want the message he can just do 2> /dev/null. Or
2>&- . That's how we do things on Linux/Unix.
$ apt show twitter-bootstrap
Package: twitter-bootstrap
State: not a real package (virtual)
N: Can't select candidate version from package twitter-bootstrap as it has no
candidate
N: Can't select versions from package 'twitter-bootstrap' as it is purely
virtual
N: No packages found
Now experimenting with apt,
$ apt show twitter-bootstrap 2>&1 | nl -b a
1
2 WARNING: apt does not have a stable CLI interface. Use with caution in
scripts.
3
4 Package: twitter-bootstrap
5 State: not a real package (virtual)
$ apt show twitter-bootstrap | nl -b a
WARNING: apt does not have a stable CLI interface. Use with caution in scripts.
1 Package: twitter-bootstrap
2 State: not a real package (virtual)
Aptitude is much more consistent,
$ aptitude show twitter-bootstrap | nl -b a
1 Package: twitter-bootstrap
2 State: not a real package
3 Provided by: libjs-twitter-bootstrap (2.0.2+dfsg-10)
$ aptitude show twitter-bootstrap
Package: twitter-bootstrap
State: not a real package
Provided by: libjs-twitter-bootstrap (2.0.2+dfsg-10)
Anyway your idea of a tty is fine for you. But not for how many users
will use these programs. Thanks.
