Sometimes I pipe articles in tin(1) through a perl script that parses the output, does something and pipes it into less; when I quit less I'm back in tin and everything is fine. However, when I press ctrl-z (happens more often than I'd think) the terminal ends up in a strange state. The output is

Stopped. Type 'fg' to restart tin

but I have no shell:

ls
(nothing)

[download]

entering "fg" doesn't take me back to tin. Killing the perl and/or less processes doesn't help either, nor does pressing 'q' (as command for less or tin).

A tin developer analysed the behaviour of tin for me: before popen(), tin does (feed.c:feed_articles() ~ line 616)

    reset_shell_mode(3ncurses);
    endwin(3ncurses);

[download]

and after pclose() (feed.c:feed_articles() ~ line 855)

    reset_prog_mode(3ncurses);
    set_keypad_on(3ncurses);

[download]

SIGTSTP causes (signal.c:handle_suspend())

    set_keypad_off(3ncurses);
    set_xclick_off(3ncurses);
    reset_shell_mode(3ncurses);
    kill(0, SIGSTOP);
    reset_prog_mode(3ncurses);
    set_keypad_on(3ncurses);
    set_xclick_on(3ncurses);

[download]

The developer claims that the double reset_shell_mode shouldn't hurt and that this looks ok (I think so as well).

He reduced my test case to

cat|less

and pressing ^Z, which works nicely, however piping through

perl -ne 'print $_;'|less

and pressing ^Z confuses perl. This looks like a perl-specific problem.

Can someone shed more light on this?

In reply to weird ctrl-z behaviour when piping from tin through perl by Anonymous Monk

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