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?
111
votes
8answers
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How can I disown a running process and associate it to a new screen shell?

I have a running program on a SSH shell. I want to pause it and be able to unpause its execution when I come back. One way I thought of doing that was to transfer its ownership to a screen shell, ...
29
votes
6answers
20k views

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) ...
141
votes
11answers
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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 ...
34
votes
4answers
5k 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 ...
35
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3answers
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What is stored in /dev/pts files and can we open them?

According to my knowledge, /dev/pts files are created for ssh or telnet sessions.
249
votes
3answers
143k views

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 ...
28
votes
2answers
14k views

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. ...
53
votes
6answers
7k 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 ...
5
votes
1answer
734 views

How do I come by this pty and what can I do with it?

It seems that a simple shell redirect from /dev/ptmx gets me a new pseudo-terminal. $ ls /dev/pts; ls /dev/pts </dev/ptmx 0 1 2 ptmx 0 1 2 3 ptmx It disappears as soon as the process that ...
28
votes
3answers
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tmux, TERM and 256 colours support

Introduction My question arises from the necessity of understanding why I have now (after multiple trials) Terminal and tmux supporting 256 colours and tput colors telling me there are only 8 of ...
11
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2answers
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What does the tilde (~) mean at the end of a filename? [duplicate]

What is the file with the ~ at the end of the filename for? $ ls # aliased to add flags -rwxrwxr-x 1 durrantm 2741 May 16 09:28 strip_out_rspec_prep_cmds.sh~* drwxrwxr-x 13 durrantm 4096 May 16 ...
43
votes
2answers
5k views

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 ...
32
votes
3answers
13k views

Terminal prompt not wrapping correctly

I have an issue where if I type in very long commands in bash the terminal will not render what I'm typing correctly. I'd expect that if I had a command like the following: username@someserver ...
19
votes
5answers
18k views

view stdout for another pts [duplicate]

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 ...
14
votes
1answer
3k 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 ...
20
votes
4answers
6k 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 ...
7
votes
2answers
2k views

Can I set my local machine's terminal colors to use those of the machine I ssh into?

I have a color scheme that I like for when I'm in a terminal, but I ssh into the machine I work on from multiple sources (locally, PuTTY, my netbook, etc.) and I want to maintain the same color scheme ...
17
votes
3answers
4k 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
votes
2answers
5k views

How to change the contents of a line on the terminal as opposed to writing a new one?

So, when wget gets a web page, it shows you a status bar that indicated how much the file(s) is/are downloaded. It looks like this: 25%[=============>______________________________________] ...
6
votes
2answers
3k views

Where does the TERM environment variable default get set?

When I open a terminal window with the GNOME Terminal emulator in the desktop GUI the shell TERM environment variable defaults to the value xterm. If I use CTL+ALT+F1 to switch to a console TTY ...
3
votes
4answers
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How to clean up the RAM memory that is being used as cache memory?

My processor is using a big part of my RAM memory as cache and I want to clean it up because of that; will it prejudice something?
8
votes
5answers
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xargs and vi - “Input is not from a terminal”

I have about 10 php.ini files on my system, located all over the place, and I wanted to quickly browse through them. I tried this command: locate php.ini | xargs vi But vi warns me Input is not ...
6
votes
2answers
2k views

How to see password as we type it

In debian wheezy terminal i type su - It ask for password, which i type but it dont show anything as Password: I want to it to show at least some asterisks as the placeholder for the password ...
4
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2answers
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Why using cat on binary files messed up the terminal and how?

If I understand correctly the cat manual: concatenate files and print on the standard output cat will take files as argument and print them on standard output. What I don't get is if I use the ...
-2
votes
2answers
889 views

Corresponding 7zip command for unzip -p -a

I have a question regarding unzip command in Unix. As of now my Unix command unzip -p -a is able to zip the file which are lesser in size. But if the file size is larger then the command is not able ...
38
votes
7answers
38k views

Disable screen blanking on text console

I'm running linux clusters, mostly on SLES10. The servers are mostly blades, accessed via remote console. There is a real console in the server room, but switched off. I would like to disable the ...
32
votes
9answers
137k views

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 ...
45
votes
3answers
21k views

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 ...
76
votes
4answers
14k views

What is the point of Ctrl-S?

Ctrl+S stops all output to the terminal which can be restarted with Ctrl+Q. But, why does Ctrl+S exist in the first place? What problem was trying to be solved by putting that control sequence in ...
34
votes
2answers
14k views

Fix terminal after displaying a binary file

I'd tried command cat with an executable file: cat /bin/ls Now I can't read any word in this terminal (Linux console). How can I fix it?
61
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2answers
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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 ...
32
votes
4answers
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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 ...
32
votes
6answers
14k 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 ...
22
votes
6answers
14k 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 ...
18
votes
1answer
2k views

Documentation on LESS_TERMCAP_* variables?

I see these pretty colors in manpages viewed with less when setting a bunch of these variables. What do they mean, where is the documentation? Is this interpreted by less or termcap? screenshot
33
votes
1answer
1k 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 ...
21
votes
4answers
24k views

How to solve the issue that a Terminal screen is messed up? (usually after a resizing)

Sometimes, a terminal screen is messed up, and when we use man ls to read the manpages, or press the UP arrow to go to previous commands in history, the screen will show characters not as the right ...
34
votes
2answers
40k views

How to signal the end of stdin input in bash

In Bash, I learned that the ending signal can be changed by here document. But by default how can I signal the end of stdin input? I happened to find that with cat and chardet, their stdin inputs can ...
18
votes
6answers
14k 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 ...
23
votes
4answers
4k 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 ...
11
votes
2answers
21k views

How can I switch between ttys without using screen?

So lets say you boot up your linux install all the way to the desktop. You start up a gnome-terminal/konsole/whatever so you have a tty to enter commands to. Now lets say I SSH into that same ...
22
votes
5answers
8k views

How can I create an alias for a git [action] command (which includes spaces)?

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 ...
9
votes
2answers
11k views

Execute command in remote active terminal

Suppose you have a terminal emulator (T1) open with a PID of 6350. From another terminal, type this command (C1): echo "ls\n" > /proc/6350/fd/0 This writes ls and the new line in T1 but does ...
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votes
2answers
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Remapping caps-lock to escape, and menu to compose, on the linux console

When running X I use a .xmodmaprc to remap certain keys thusly: ! Make it so that both Caps Lock and Escape do Escape clear Lock keysym Caps_Lock = Escape ! Remap the menu key as Compose keysym Menu ...
4
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5answers
1k views

Multiple terminals at once without an X server

There is a way to visualize multiple terminals at the same time without running a Xorg session ? I have a really low profile machine that could be great for some basic stuff but has an horrible ...
3
votes
1answer
432 views

Using a variable inside a sequence of commands in bash to supplement an existing string - syntax error or flawed design?

I'm using the following sequence of commands in my .bashrc file to alter the appearance of my linux terminal. It fills the screen line by line with a pattern made out of characters. There is no ...
2
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1answer
1k views

Orphan process's parent id is not 1 when parent process executed from GNOME Terminal

I start a new process from GNOME Terminal and then this process fork a child. But when I killed the parent process the orphaned process's parent id became something other than 1 which represent init ...
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vote
2answers
77 views

Disable scroll inside Xfce terminal / Avoid scrolling through command history

Is there a way to disable scrolling through command history for the Xfce terminal? I don't wish to rely on palm rejection, I'd just like it disabled when I'm using the terminal. Specifically I'm ...
0
votes
1answer
142 views

How are virtual consoles related to traditional computer terminals?

This is extracted (with some rewording) from Computer terminal and virtual console, which has been closed with a hatnote linking to What is the exact difference between a 'terminal', a ...