A terminal is an environment for text input/output. Inside the terminal, one runs command-line and text mode programs (including shells).

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What is the exact difference between a 'terminal', a 'shell', a 'tty' and a 'console'?

I think these terms almost refer to the same thing, when used loosely: terminal shell tty console What exactly does each of these terms refer to?
78
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2answers
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How to unfreeze after accidentally pressing Ctrl-S in a terminal?

It's a situation that has happened quite often to me: after I press (with a different intention) Ctrl-S in a terminal, the interaction (input or output) with it is frozen. It's probably a kind of ...
58
votes
6answers
54k views

How to split the terminal into more than one “view”?

From vi, if you issue the command :sp, the screen splits into two "views", allowing you to edit more than one file from the same terminal. Along those same lines, is there a way to have multiple ...
53
votes
6answers
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How can I close a terminal without killing the command running in it?

Sometimes I want to start a process and forget about it. If I start it from the command line, like this: redshift I can't close the terminal, or it will kill the process. Can I run a command in ...
49
votes
2answers
2k views

Clear / erase a mistyped invisible password on a shell / terminal in Linux

One thing that annoys me using Linux's terminal is when I have to type a invisble password, like when you run ssh. Sometimes I mistype one or more letters and then I have to press backspace key a few ...
44
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7answers
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How safe is it to cat an arbitrary file?

Sometimes when I cat a binary file by mistake, my terminal gets garbled up. Nothing a quick reset can't fix, but couldn't an attacker theoretically create a file that, when displayed on a terminal, ...
31
votes
6answers
3k views

Can I configure my shell to print STDERR and STDOUT in different colors?

I want to set my terminal up so stderr is printed in a different color than stdout; maybe red. This would make it easier to tell the two apart. Is there a way to configure this in .bashrc? If not, is ...
30
votes
2answers
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Can a terminal emulator be as fast as TTY 1-6?

I've been trying various terminal emulators lately, from the built-in gnome-terminal, aterm, xterm, wterm, to rxvt. The test I've been doing is in this order: Open up a tmux window with 2 panes The ...
29
votes
1answer
4k views

Kill an unresponsive ssh session without closing the terminal

Is there a way to disconnect from an SSH session that has become unresponsive without killing the whole terminal? Specifically I'm using konsole, and the machine I'm working with sometimes hangs, but ...
29
votes
1answer
698 views

What happens when Ctrl + Alt + F<Num> is pressed?

I am looking for an explanation of what happens in Linux when this key combination is pressed to change the current terminal. In particular, what software component intercepts this key combination and ...
27
votes
3answers
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How can I break away from an SSH session that has crashed?

Many times I have an SSH session that doesn't respond anymore (for example, when I lose internet connection and then reconnect). Ctrl+C, Ctrl+D, Ctrl+Z and a zillion of key presses don't have any ...
24
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5answers
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How does clear command work?

I was recently trying to learn more about how the shell works and was looking at how the clear command works. The executable is located in /usr/bin/clear and it seems to print out a bunch of blank ...
19
votes
3answers
8k views

How to remove “You have mail” welcome message

When I open up my terminal it says "you have mail", anyone has any idea of why? I am running OS X, but since it too is based on Unix and relies on files such as bashrc, bash_profile etc. I thought ...
19
votes
4answers
3k views

What happens to the output of a process that has been disowned and lost its terminal?

If I close the virtual terminal, where some process was started, does the output just go straight to /dev/null, or can it pollute memory somehow? Can I anyhow grab the output to continue reading it at ...
18
votes
6answers
2k views

Using VI keys to edit shell commands in UNIX

I used to have a co-worker who was really good at UNIX. He showed me how to use Vi key bindings to edit my shell commands. He placed the command in a file that ran every time I logged in. Since ...
18
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6answers
6k views

How to check if bash can print colors

I want to know if there's any way to check if my program can output terminal output using colors or not. Running commands like less and looking at the output from a program that outputs using ...
18
votes
1answer
22k views

How to recover a 'lost' screen session?

Somehow I managed to close a screen window without screen 'noticing' it, so the session is still flagged as attached. This prevents me from re-attaching to this session. What can I do? ...
18
votes
2answers
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Output from ls has newlines but displays on a single line. Why?

I think I may be overlooking a relatively fundamental point regarding shell. Output from the ls command by default separates output with newlines, but the shell displays the output on a single line. ...
17
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4answers
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How to attach terminal to detached process?

I have detached a process from my terminal, like this: $ process & That terminal is now long closed, but process is still running and I want to send some commands to that process's stdin. Is ...
17
votes
3answers
11k views

SSH inside SSH fails with “stdin: is not a tty”

I'm trying to connect to machine one with ssh and then connect to another machine two with ssh, but I get this error. ssh user@computerone.com 'ssh otheruser@computertwo.com' stdin: is not a tty ...
16
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9answers
1k views

How to make sure that a command is not interrupted, even if terminal is closed? [duplicate]

In Linux. Say I want to run a command and it takes too long. I just want to ensure it's done. How?
16
votes
5answers
7k views

How can I close a terminal without killing its children (without running `screen` first)?

sometimes I run an app in the gnome-terminal, but then I suddenly have to restart gnome or something. I guess the answer to the question is also useful then I want to disconnect from SSH where ...
15
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4answers
3k views

How can I create an alias for a command that includes a space?

Most of my my aliases are of this form: alias p='pwd' I want to alias git commit so that it does git commit -v But trying to create an alias with a space gives an error: $ alias 'git commit'='git ...
15
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4answers
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Removing control chars (including console codes / colours) from script output

I can use the "script" command to record an interactive session at the command line. However, this includes all control characters and colour codes. I can remove control characters (like backspace) ...
15
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3answers
1k views

How to know the “level” of shells I am in?

If I open a terminal like xterm I will have a shell. Then if I use ssh or zsh I will have another "level" of shell. Is there a way to know how many times I have to Ctrl+D or type exit to exit all of ...
15
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1answer
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Is it possible to have vim key bindings in terminal?

I'm getting used to vim bindings (like pressing w to go to word, dw to delete a word, and such) and it's modes (insert, normal, visual), and, out of curiosity would like to know: is there some kind of ...
15
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1answer
473 views

How does “man” restore the screen when I quit the program?

If I open a man page of a program like cat or ls, it prints (may not be the appropriate word) the contents of the man page and when I press q, it shows the screen just like before invoking the man ...
15
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1answer
4k views

GNU Screen: new window name change

I can change the name of a window with Ctrl-a Shift-a. Instead of editing several window names by hand, is there a way to have them automatically named after the current directory?
14
votes
6answers
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How to connect to a serial port as simple as using SSH?

Is there a way to connect to a serial terminal just as you would do with SSH? There must be a simpler way than tools such as Minicom, like this $ serial /dev/ttyS0 I know I can cat the output ...
14
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5answers
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Best way to use a shell with Cygwin in Windows 7

I installed Cygwin, to be disappointed that bash by default runs within "cmd.exe". I googled around and found Console2. It's not a particularly well-designed application, as doing adjustments is ...
14
votes
3answers
744 views

Which terminal type am I using?

I have tested this with both Ubuntu 12.04 and Debian 7. When I do echo $TERM I get xterm But if I use the dropdown menu "help" > "about" then it says gnome terminal 3.4.1.1. Does this mean I am ...
14
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2answers
785 views

Is it harmful to close a terminal window without properly exiting an application?

Using Ubuntu 12.04 LTS, my question is that if I started an application in a terminal window, then is there anything bad about just closing the terminal window without exiting the application properly ...
14
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3answers
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What are pseudo terminals (pty/tty)?

This might be really basic question but I want to understand it thoroughly. What is a pseudo terminal? (tty/pty) Why do we need them? How they got introduced and what was the need for it? Are they ...
13
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5answers
35k views

How to find application's path from command line?

For example, I have git installed on my system. But I don't remember where I installed it, so which command is fit to find this out?
13
votes
4answers
3k views

How to scroll in a terminal using keyboard?

How can I scroll in bash using only the keyboard? If it's not possible in bash, are there any other shells that support this?
13
votes
4answers
3k views

Why do some commands 'hang' the terminal until they've finished?

Sometimes you run a program from the terminal, say, lxpanel†. The terminal won't drop you back to the prompt, it'll hang. You can press Ctrl+C to get back to the prompt, but that will kill ...
13
votes
4answers
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Is there a way to lock command line?

For example, in X session, I can use Ctrl-Alt-L to lock the screen, so it would ask for password to unlock and prevent somebody from messing with mine computer. But if I have an open terminal session ...
13
votes
3answers
260 views

What are the responsibilities of each Pseudo-Terminal (PTY) component (software, master side, slave side)?

I am trying to figure out how a tty works1 (the work-flow and responsibilities of each elements). I have read several interesting articles about it, but there are still some blurry areas. This is ...
12
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1answer
1k views

What protocol/standard is used by terminals?

I was wondering how the "GUI" of a command line application is communicated over a network. Most of the time, it's quite simple (plain text / input) but sometimes it's more complex (aptitude). Is it ...
12
votes
3answers
306 views

How to redirect whatever I enter in terminal to file

I am a novice just learning Fedora 13. I just wanted to know if its possible to redirect whatever I type in the terminal to a file, so that I would be able to see from the file, that a particular ...
12
votes
4answers
8k views

view stdout for another pts

Here is the situation. I left my pc at home doing an rsync from a 2TB hard drive to another 2TB hard drive (it's going to take a while since they are both USB 2.0). I am now at work and I have ssh-ed ...
12
votes
2answers
1k views

Can I configure bash to execute “clear” before every command typed in the console?

I would like to configure bash to execute clear command every time I type some command in the terminal (before executing my command). How can I do that? I'm using Debian Linux.
11
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8answers
973 views

Is screen useful?

When I need to open different processes or terminals that I need to check, I just open a new tab in my terminal and use different workspaces in my machine to keep everything organized. I do some web ...
11
votes
4answers
988 views

How did they manage to drive a Unix computer before mice and copy & paste?

Since Unix is 40 years old, Unix is older than the invention of the computer mouse. (actually only 3 years if Unix is from 1969 and the mouse from 1972) How in the world did a new user do anything ...
11
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5answers
6k views

How to clear terminal completely?

When we use clear command or Ctrl+L in terminal, it clears terminal but we can still scroll back to view the last used commands. Is there a way to completely clear the terminal?
11
votes
4answers
7k views

Can a Gnome Terminal profile use UTF-8 by default?

I am on an Ubuntu (I think) system. I don't have root, so I can't change the locale. I want to make my default terminal profile use UTF-8 by default. There should be a way to do this, either in the ...
11
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4answers
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Converting colored output into html

There are tools providing coloured output: dwdiff -c File1 File2 # word level diff grep --color=always # we all know this guy ... The question is: How to convert their colored output of arbitrary ...
11
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1answer
115 views

Include colouring in GNU ls time-style

I know, I can specify custom time format for ls like this ls -lAF --time-style="+ %Y-%b-%d %H:%M:%S" --color=always but I would like to "smuggle in" colors inside the time format. For example, I ...
11
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2answers
372 views

Can the empty spaces/background in a terminal be replaced with a random(but pretty) pattern of ASCII characters?

Context and Question There are many ways to colorize the terminal and shell environment. The output of individual commands, such as ls and grep, can also be colorized. Not directly related but ...
11
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1answer
878 views

Ctrl-C does not work with pppd non-detached session

I have a Mini2440 ARM Board, and I have put a base Debian 6.0 system on it using multistrap. I have used tmux to run several processes in defferent windows from /etc/rc.local. I connect to the board ...