What is the Linux equivalent to DOS pause?

Question

I have a Bash shell script in which I would like to pause execution until the user presses a key. In DOS, this is easily accomplished with the pause command. Is there a Linux equivalent I can use in my script?

Dole

Answer 1

read does this:

user@host:~$ read -n1 -r -p "Press any key to continue..." key
[...]
user@host:~$ 

The -n1 specifies that it only waits for a single character. The -r puts it into raw mode, which is necessary because otherwise, if you press something like backslash, it doesn't register until you hit the next key. The -p specifies the prompt, which must be quoted if it contains spaces. The key argument is only necessary if you want to know which key they pressed, in which case you can access it through $key.

If you are using Bash, you can also specify a timeout with -t, which causes read to return a failure when a key isn't pressed. So for example:

read -t5 -n1 -r -p 'Press any key in the next five seconds...' key
if [ "$?" -eq "0" ]; then
    echo 'A key was pressed.'
else
    echo 'No key was pressed.'
fi

Tankage

Strictly speaking, that would be "Enter any non-NUL character to continue". Some keys don't send any character (like Ctrl...) and some send more than one (like F1, Home...). bash ignores NUL characters. – Syzygy

Usually it's a better idea to ask for a specific key like enter, space or Y. "ANY" can be confusing to some users, there is a TAB-key so why no ANY-key and for sure there are keys that are potentially dangerous like ESCAPE, CTRL, CMD, the power button, etc. This isn't so relevant anymore today, because nowadays the console is usually only used by advanced computer users that will interpret "ANY key" correctly. The Apple 2 Design Manual, tough quite old, has an interesting section devoted to this subject (apple2scans.net/files/1982-A2F2116-m-a2e-aiiedg.pdf). – Augustaaugustan

If you instead use the message Press a key to continue... then even novice users will be able to find the a key and press it ;o) – Fester

This will have issues with command | myscript.sh or myscript.sh | command. See this answer for a solution. – Electrodialysis

If anyone gets read: 1: read: Illegal option -n make sure to wrap your command in bash -c 'command && command' etc. as that error is likely from sh. I am doing this in a Lando wrapper command. – Codi

Is there a way to do this only when script was run by double-clicking it in the GUI? – Tannate

@Tannate You should open your own question and include more details, such as which GUI you are using. – Tankage

Answer 2

I use these ways a lot that are very short, and they are like @theunamedguy and @Jim solutions, but with timeout and silent mode in addition.

I especially love the last case and use it in a lot of scripts that run in a loop until the user presses Enter.

Commands

• Enter solution

  read -rsp $'Press enter to continue...\n'
  

• Escape solution (with -d $'\e')

  read -rsp $'Press escape to continue...\n' -d $'\e'
  

• Any key solution (with -n 1)

  read -rsp $'Press any key to continue...\n' -n 1 key
  # echo $key
  

• Question with preselected choice (with -ei $'Y')

  read -rp $'Are you sure (Y/n) : ' -ei $'Y' key;
  # echo $key
  

• Timeout solution (with -t 5)

  read -rsp $'Press any key or wait 5 seconds to continue...\n' -n 1 -t 5;
  

• Sleep enhanced alias

  read -rst 0.5; timeout=$?
  # echo $timeout
  

Explanation

-r specifies raw mode, which don't allow combined characters like "\" or "^".

-s specifies silent mode, and because we don't need keyboard output.

-p $'prompt' specifies the prompt, which need to be between $' and ' to let spaces and escaped characters. Be careful, you must put between single quotes with dollars symbol to benefit escaped characters, otherwise you can use simple quotes.

-d $'\e' specifies escappe as delimiter charater, so as a final character for current entry, this is possible to put any character but be careful to put a character that the user can type.

-n 1 specifies that it only needs a single character.

-e specifies readline mode.

-i $'Y' specifies Y as initial text in readline mode.

-t 5 specifies a timeout of 5 seconds

key serve in case you need to know the input, in -n1 case, the key that has been pressed.

$? serve to know the exit code of the last program, for read, 142 in case of timeout, 0 correct input. Put $? in a variable as soon as possible if you need to test it after somes commands, because all commands would rewrite $?

Kaon

+1 for explaining -s; man read and read --help help didn't help on Ubuntu 10.04.1 LTS. Edit: help read did; is the rest deprecated? – Tokenism

1+ for the great explanation: but i got read: -i: invalid option for the ex. read -rp $'Are you sure (Y/n) : ' -ei $'Y' key;on #osx read -rp $'kill-server: Are you sure (Y/n) : ' -d $'Y' key; works for me instead. ` – Kokoschka

I don't know how it works on OSX but I've made some test and -i works perfectly on Ubuntu, also I don't know how if -d works the same way on OSX. – Kaon

one can work around prompt really quick and nice by using an echo before read, eventually echo -n – Hardshell

I especially like the timeout solution. – Kings

Answer 3

This worked for me on multiple flavors of Linux, where some of these other solutions did not (including the most popular ones here). I think it's more readable too...

echo Press enter to continue; read dummy;

Note that a variable needs to be supplied as an argument to read.

Engagement

this answer solve my problem, if I copy and paste this line and for some reason I got more lines appended, the appended lines are not executed , like was with DOS pause – Viosterol

Answer 4

read without any parameters will only continue if you press enter. The DOS pause command will continue if you press any key. Use read –n1 if you want this behaviour.

Cogitative

Answer 5

read -n1 is not portable. A portable way to do the same might be:

(   trap "stty $(stty -g;stty -icanon)" EXIT
    LC_ALL=C dd bs=1 count=1 >/dev/null 2>&1
)   </dev/tty

Besides using read, for just a press ENTER to continue prompt you could do:

sed -n q </dev/tty

Jessy

status=none is not portable either. Redirect stdout and stderr to /dev/null instead. read -r line < /dev/tty would be enought for press ENTER.... – Syzygy

@StephaneChezales thanks - i didnt know that. ill fix it now. Thanks again - fixed. Youre a bottomless well of worthwhile information, by the way. – Jessy

Also note the settings=$(stty -g); stty raw; dd ...; stty "$settings" to save and restore the tty settings. – Syzygy

@StephaneChezales - im not at a computer - do you think the tr edit thing could work too? – Jessy

No, because tr would buffer its output as its a pipe, and non-US keyboards have keys that send characters outside the \1-\177 range. dd is the idiomatic way here. – Syzygy

@StephaneChezales - thanks again. I'll pull it. I think there's a way to get canonical mode tty's to translate like that, though. I cant remember. I'll check again when i get to a computer. – Jessy

If you're redirecting dd's stdin, then you should probably redirect stty's as well (wrap the whole thing inside {...} < /dev/tty. Also, like for @Jim's answer, if you want to read all the characters sent upon a key press, you'd need to do something like: (settings=$(stty -g); stty raw min 99 time 1; dd count=1 bs=99 > /dev/null 2>&1; stty "$settings") < /dev/tty. – Syzygy

raw implies -isig which may not be desirable. You might also want to flush the input buffer before issuing the prompt (stty -icanon min 0 time 0; cat > /dev/null). – Syzygy

@StephaneChezales - thats kinda funny - i was just looking at what i might do with stty -icanon min N - but it might have to wait til i get an actual screen/keyboard. just typing this comment on the tablet is a chore... i think i should be using -icanon anyway to preserve interrupts. i guess you put in that comment before i could hit submit. we're thinking along the same lines, though, i guess. – Jessy

"probable" ?!? ... WHAT IS THAT MEAN ?!? ... EXACTLY ?!? read -n1 is working thank you very much, and is easy an simple – Hardshell

I used read -rsp $'Press any key to continue...\n' -n 1 key before, but it always failed to reset my terminal's settings, so I'd have to run reset afterwards. This command works perfectly for me (on macOS 10.15)! I also added stty -echo after the trap line because I didn't want to see the character I typed. – Juster

Answer 6

If you just need to pause a loop or script, and you're happy to press Enter instead of any key, then read on its own will do the job.

do_stuff
read
do_more_stuff

It's not end-user friendly, but may be enough in cases where you're writing a quick script for yourself, and you need to pause it to do something manually in the background.

Pegmatite

This is true, but for the database it is most helpful to show an example. – Franckot

Thanks, I took your advice on board. Just writing a command name isn't very clear in hindsight. – Pegmatite

Answer 7

This function works in both bash and zsh, and ensures I/O to the terminal:

# Prompt for a keypress to continue. Customise prompt with $*
function pause {
  >/dev/tty printf '%s' "${*:-Press any key to continue... }"
  [[ $ZSH_VERSION ]] && read -krs  # Use -u0 to read from STDIN
  [[ $BASH_VERSION ]] && </dev/tty read -rsn1
  printf '\n'
}
export_function pause

Put it in your .{ba,z}shrc for Great Justice!

Electrodialysis

Where is "export_function" defined? – Kings

Should be the selected answer: it can be used in a script already reading some input. – Lesialesion

Answer 8

This fixes it so pressing any key other than ENTER will still go to a new line

read -n1 -r -s -p "Press any key to continue..." ; echo

---

it's better than windows pause, because you can change the text to make it more useful

read -n1 -r -s -p "Press any key to continue... (cant find the ANY key? press ENTER) " ; echo

Pistole

I think your solution is the only one that actually resembles the prompt from Windows, where you are asked to type any key on the same line. Except that before every dot . in the prompt, there is an additional space, for some reason – Binette

Doesn't work in system() call. E.g. this C++ code system("read -n1 -r -s -p \"Press any key to continue...\" ; echo"); displays an error: sh: 1: read: Illegal option -n. Though read -n1 command works fine from the same Ubuntu shell. The pause command can be used as system("pause"); In Windows programs. – Beatrisbeatrisa

Answer 9

Try this:

function pause(){
  read -p "$*"
}

Here read is to read a line of input, and with -p is to give prompt. And $* will simply read from args.

How to pass it to script:

./test Some-blah blah with space withoutspace

Now it gets expanded like this:

read -p Some-blah blah with space withoutspace

So in the terminal you will get prompt for Some-blah blah with space withoutspace, they you can enter your value as response to this prompt.

Chellean

Can someone please explain why this is downvoted? Is it for lack of content or is this a bad solution? – Finalist

@Finalist This does not show usage of the function that is created; plus this lack any explanation. – Overleap

Agreed. Can you please show an example of how this function is invoked? – Franckot

Answer 10

Yes to using read - and there are a couple of tweaks that make it most useful in both cron and in the terminal.

Example:

time rsync (options)
read -n 120 -p "Press 'Enter' to continue..." ; echo " "

The -n 120 makes the read statement time out after 2 minutes so it does not block in cron.

In terminal it gives 2 minutes to see how long the rsync command took to execute.

Then the subsequent echo is so the subsequent bash prompt will appear on the next line.

Otherwise it will show on the same line directly after "continue..." when Enter is pressed in terminal.

Franckot