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On Sun, Mar 19, 2017 at 09:49:50AM +0100, Kai Krakow wrote |
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> Hello! |
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> |
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> More and more of my Gentoo systems are exhibiting the following |
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> strange and unexpected behavior: |
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> |
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> After ctrl+c'ing out of programs like tailf, SSH password prompts, in |
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> the middle of a shell scripts, the shell echo is not restored - that |
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> is: If I type characters I no longer see the characters (but they are |
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> received and can be executed by "enter"). If experiencing this, I have |
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> to ctrl+c again to discard what I was typing, the blindly type "reset" |
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> to reset the terminal, then echo is enabled again. |
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|
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"It's not a bug; it's a feature". It's caused by some programs. See |
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http://askubuntu.com/questions/171449/shell-does-not-show-typed-in-commands-reset-works-but-what-happened |
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for a detailed explanation. Executive summary... some programs, e.g. |
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vim, can be run from the command line, and they accept certain control |
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characters (CTRL-V, CTRL-I, etc) as valid input. These characters would |
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normally be echo'd back to the user's terminal by the kernel's tty |
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subsystem. This would foul up the application's screen display. To |
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avoid that, the application turns off echoing to the tty when it starts |
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up. It also restores echoing ***IF IT EXITS PROPERLY***. This also |
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applies to when a program issues a password prompt, where you obviously |
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want echoing turned off. If killed with CTRL-C or "kill -9" or "kill |
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-15", it doesn't have a chance to restore echoing, and you get the |
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situation you described. |
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|
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-- |
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Walter Dnes <waltdnes@××××××××.org> |
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I don't run "desktop environments"; I run useful applications |