Re: Bug in bash 4.4-beta: suspending and restarting "man" program

[Keith Thompson]

I've found another symptom of the problem. It has something to do with

the handling of the TSTP signal (normally sent by typing Ctrl-Z).

Running bash 4.4-beta, I type the "cat" command. While "cat" is running,

I type Ctrl-Z.

Normally this should suspend the "cat" process and give me a shell prompt,

but nothing visible happens.

Normally I can achieve the same effect by running "kill -TSTP PID",

where PID is the process id of the "cat" process, from another terminal.

This also does nothing.

I *can* suspend the "cat" process by typing "kill -STOP PID" from

another terminal.  After doing that, I can restore it by typing "fg"

at the bash prompt (but Ctrl-Z still doesn't work).

This problem occurs with bash 4.4-beta on Debian 6.0.10.  It does not

occur with bash 4.4-beta on Linux Mint 17.2, or with bash 4.3.30 on

Debian 6.0.10.

On Wed, Oct 28, 2015 at 7:02 PM, Keith Thompson <keithsthompson@gmail.com> wrote:

I'm running bash 4.4-beta, built from bash-4.4-beta.tar.gz, on two

different x86_64 systems, one running Debian 6.0.10 and another running

Linux Mint 17.3.

On both systems, if I run "man rm" (for example) I can read the "rm(1)"

man page using "less" (my $MANPAGER is set to "less -s -r").  If I then

type Ctrl-Z, the "man" and "pager" processes are suspended and the screen

is restored its previous state.

On the Debian system, I don't get a new shell prompt (this is the

bug). The terminal continues to accept and echo input, but it's otherwise

stuck.  Ctrl-C and Ctrl-Z are echoed as "^C" and "^Z", but are otherwise

ignored.  I can recover by killing the "man" process from another window.

On the Linux Mint system, this problem does not occur.  Typing Ctrl-Z

gives me a new shell prompt, and the "man rm" process shows up in the

"jobs" listing.

The problem does not occur on Debian 6 using /bin/bash (version 4.1.5).

I don't see the problem when I invoke "less" or "vi" directly. I've

seen the problem when I'm in an editor (vim) invoked from "git commit".

So apparently it has something to do with a full-screen program invoked

by some other program.

Let me know if I can provide more information (Debian 6 is fairly old, so

you might not have a running copy).

--

Keith Thompson <Keith.S.Thompson@gmail.com>

--

Keith Thompson <Keith.S.Thompson@gmail.com>