Here is roughly a snippet that you want. Let me find out how to forward the arguments.

read -p "Are you sure you want to continue? <y/N> " prompt if [[ $prompt == "y" || $prompt == "Y" || $prompt == "yes" || $prompt == "Yes" ]] then # http://stackoverflow.com/questions/1537673/how-do-i-forward-parameters-to-other-command-in-bash-script else exit 0 fi 

Watch out for yes | command name here :)

Confirmations are easily bypassed with carriage returns, and I find it useful to continually prompt for valid input.

Here's a function to make this easy. "invalid input" appears in red if Y|N is not received, and the user is prompted again.

prompt_confirm() { while true; do read -r -n 1 -p "${1:-Continue?} [y/n]: " REPLY case $REPLY in [yY]) echo ; return 0 ;; [nN]) echo ; return 1 ;; *) printf " \033[31m %s \n\033[0m" "invalid input" esac done } # example usage prompt_confirm "Overwrite File?" || exit 0 

You can change the default prompt by passing an argument

To avoid explicitly checking for these variants of 'yes' you could use the bash regular expression operator '=~' with a regular expression:

read -p "Are you sure you want to continue? <y/N> " prompt if [[ $prompt =~ [yY](es)* ]] then (etc...) 

That tests whether the user input starts with 'y' or 'Y' and is followed by zero or more 'es's.

This may be a hack:

as in question In Unix / Bash, is "xargs -p" a good way to prompt for confirmation before running any command?

we can using xargs to do the job:

echo ssh://[email protected]//somepath/morepath | xargs -p hg push 

of course, this will be set as an alias, like hgpushrepo

Example:

$ echo foo | xargs -p ls -l ls -l foo?...y -rw-r--r-- 1 mikelee staff 0 Nov 23 10:38 foo $ echo foo | xargs -p ls -l ls -l foo?...n $ 

This may be a little too short, but for my own private use, it works great

read -n 1 -p "Push master upstream? [Y/n] " reply; if [ "$reply" != "" ]; then echo; fi if [ "$reply" = "${reply#[Nn]}" ]; then git push upstream master fi 

The read -n 1 just reads one character. No need to hit enter. If it's not a 'n' or 'N', it is assumed to be a 'Y'. Just pressing enter means Y too.

(as for the real question: make that a bash script and change your alias to point to that script instead of what is was pointing to before)

No pressing enter required

Here's a longer, but reusable and modular approach:

• Returns 0=yes and 1=no
• No pressing enter required - just a single character
• Can press enter to accept the default choice
• Can disable default choice to force a selection
• Works for both zsh and bash.

Defaulting to "no" when pressing enter

Note that the N is capitalsed. Here enter is pressed, accepting the default:

$ confirm "Show dangerous command" && echo "rm *" Show dangerous command [y/N]? 

Also note, that [y/N]? was automatically appended. The default "no" is accepted, so nothing is echoed.

Re-prompt until a valid response is given:

$ confirm "Show dangerous command" && echo "rm *" Show dangerous command [y/N]? X Show dangerous command [y/N]? y rm * 

Defaulting to "yes" when pressing enter

Note that the Y is capitalised:

$ confirm_yes "Show dangerous command" && echo "rm *" Show dangerous command [Y/n]? rm * 

Above, I just pressed enter, so the command ran.

No default on enter - require y or n

$ get_yes_keypress "Here you cannot press enter. Do you like this" Here you cannot press enter. Do you like this [y/n]? k Here you cannot press enter. Do you like this [y/n]? Here you cannot press enter. Do you like this [y/n]? n $ echo $? 1 

Here, 1 or false was returned. Note no capitalisation in [y/n]?

Code

# Read a single char from /dev/tty, prompting with "$*" # Note: pressing enter will return a null string. Perhaps a version terminated with X and then remove it in caller? # See https://unix.stackexchange.com/a/367880/143394 for dealing with multi-byte, etc. function get_keypress { local REPLY IFS= >/dev/tty printf '%s' "$*" [[ $ZSH_VERSION ]] && read -rk1 # Use -u0 to read from STDIN # See https://unix.stackexchange.com/q/383197/143394 regarding '\n' -> '' [[ $BASH_VERSION ]] && </dev/tty read -rn1 printf '%s' "$REPLY" } # Get a y/n from the user, return yes=0, no=1 enter=$2 # Prompt using $1. # If set, return $2 on pressing enter, useful for cancel or defualting function get_yes_keypress { local prompt="${1:-Are you sure} [y/n]? " local enter_return=$2 local REPLY # [[ ! $prompt ]] && prompt="[y/n]? " while REPLY=$(get_keypress "$prompt"); do [[ $REPLY ]] && printf '\n' # $REPLY blank if user presses enter case "$REPLY" in Y|y) return 0;; N|n) return 1;; '') [[ $enter_return ]] && return "$enter_return" esac done } # Credit: http://unix.stackexchange.com/a/14444/143394 # Prompt to confirm, defaulting to NO on <enter> # Usage: confirm "Dangerous. Are you sure?" && rm * function confirm { local prompt="${*:-Are you sure} [y/N]? " get_yes_keypress "$prompt" 1 } # Prompt to confirm, defaulting to YES on <enter> function confirm_yes { local prompt="${*:-Are you sure} [Y/n]? " get_yes_keypress "$prompt" 0 } 

Add the following to your /etc/bashrc file. This script adds a resident "function" instead of an alias called "confirm".

function confirm( ) { #alert the user what they are about to do. echo "About to $@...."; #confirm with the user read -r -p "Are you sure? [Y/n]" response case "$response" in [yY][eE][sS]|[yY]) #if yes, then execute the passed parameters "$@" ;; *) #Otherwise exit... echo "ciao..." exit ;; esac } 

read -r -p "Are you sure? [Y/n]" response response=${response,,} # tolower if [[ $response =~ ^(yes|y| ) ]] || [[ -z $response ]]; then your-action-here fi 

Well, here's my version of confirm, modified from James' one:

function confirm() { local response msg="${1:-Are you sure} (y/[n])? "; shift read -r $* -p "$msg" response || echo case "$response" in [yY][eE][sS]|[yY]) return 0 ;; *) return 1 ;; esac } 

These changes are:

1. use local to prevent variable names from colliding
2. read use $2 $3 ... to control its action, so you may use -n and -t
3. if read exits unsuccessfully, echo a line feed for beauty
4. my Git on Windows only has bash-3.1 and has no true or false, so use return instead. Of course, this is also compatible with bash-4.4 (the current one in Git for Windows).
5. use IPython-style "(y/[n])" to clearly indicate that "n" is the default.

I like to exit as soon as possible if the user isn't sure, and I like the code to be readable and short. Depending on whether you'd like the user to press Return after their answer or not,

With pressing Return,

read -p "Warning: something scary: Continue (Y/N)? " reply [ "$reply" != "Y" ] && [ "$reply" != "y" ] && echo "Aborting" && exit 1 echo "Scary thing" 

or if you prefer not to wait for the user to press Return,

read -n1 -p "Warning: something scary: Continue (Y/N)? " reply echo "" [ "$reply" != "Y" ] && [ "$reply" != "y" ] && echo "Aborting" && exit 1 echo "Scary thing" 

The other answers have the background on that -n1 flag and other options for read. The echo "" in the 2nd variant is to make subsequent output appear on a new line since the user doesn't have to press Return, so no newline has been echoed to the terminal. Also notice $reply being in quotation marks thus "$reply" to handle the situation where the user presses Return without specifying Y or N resulting in $reply being empty; the quotation marks prevent this breaking the tests, as discussed here.

This version allows you to have more than one case y or Y, n or N

1. Optionally: Repeat the question until an approve question is provided

2. Optionally: Ignore any other answer

3. Optionally: Exit the terminal if you want

   confirm() { echo -n "Continue? y or n? " read REPLY case $REPLY in [Yy]) echo 'yup y' ;; # you can change what you do here for instance [Nn]) break ;; # exit case statement gracefully # Here are a few optional options to choose between # Any other answer: # 1. Repeat the question *) confirm ;; # 2. ignore # *) ;; # 3. Exit terminal # *) exit ;; esac # REPLY='' } 

Notice this too: On the last line of this function clear the REPLY variable. Otherwise if you echo $REPLY you will see it is still set until you open or close your terminal or set it again.

Late to the game, but I created yet another variant of the confirm functions of previous answers:

confirm () { read -r -p "$(echo $@) ? [y/N] " YESNO if [ "$YESNO" != "y" ]; then echo >&2 "Aborting" exit 1 fi CMD="$1" shift while [ -n "$1" ]; do echo -en "$1\0" shift done | xargs -0 "$CMD" || exit $? } 

To use it:

confirm your_command 

Features:

• prints your command as part of the prompt
• passes arguments through using the NULL delimiter
• preserves your command's exit state

Bugs:

• echo -en works with bash but might fail in your shell
• might fail if arguments interfere with echo or xargs
• a zillion other bugs because shell scripting is hard

Try,

 #!/bin/bash pause () { REPLY=Y while [ "$REPLY" == "Y" ] || [ "$REPLY" != "y" ] do echo -e "\t\tPress 'y' to continue\t\t\tPress 'n' to quit" read -n1 -s case "$REPLY" in "n") exit ;; "N") echo "case sensitive!!" ;; "y") clear ;; "Y") echo "case sensitive!!" ;; * ) echo "$REPLY is Invalid Option" ;; esac done } pause echo "Hi" 

This isn't exactly an "asking for yes or no" but just a hack: alias the hg push ... not to hgpushrepo but to hgpushrepoconfirmedpush and by the time I can spell out the whole thing, the left brain has made a logical choice.

Not the same, but idea that works anyway.

#!/bin/bash i='y' while [ ${i:0:1} != n ] do # Command(s) read -p " Again? Y/n " i [[ ${#i} -eq 0 ]] && i='y' done 

Output:
Again? Y/n N
Again? Y/n Anything
Again? Y/n 7
Again? Y/n &
Again? Y/n nsijf
$

Now only checks 1st character of $i read.

Below code is combining two things

1. shopt -s nocasematch that will take care of case insensitive

2. and if condition that will accept both the input either you pass yes,Yes,YES,y.

   shopt -s nocasematch

   if [[ sed-4.2.2.$LINE =~ (yes|y)$ ]]

   then exit 0

   fi

Here is my solution that using localised regex. So in german also "j" for "Ja" would be interpreted as yes.

First argument is the question, if the second argument is "y" than yes would be the default answer otherwise no would be the default answer. The return value is 0 if the answer was "yes" and 1 if the answer was "no".

function shure(){ if [ $# -gt 1 ] && [[ "$2" =~ ^[yY]*$ ]] ; then arg="[Y/n]" reg=$(locale noexpr) default=(0 1) else arg="[y/N]" reg=$(locale yesexpr) default=(1 0) fi read -p "$1 ${arg}? : " answer [[ "$answer" =~ $reg ]] && return ${default[1]} || return ${default[0]} } 

Here is a basic usage

# basic example default is no shure "question message" && echo "answer yes" || echo "answer no" # print "question message [y/N]? : " # basic example default set to yes shure "question message" y && echo "answer yes" || echo "answer no" # print "question message [Y/n]? : " 

I know this is an old question but this might help someone, it hasn't been addressed here.

I have been asked how to use rm -i in a script which is receiving input from a file. As file input to a script is normally received from STDIN we need to change it, so that only the response to the rm command is received from STDIN. Here's the solution:

#!/bin/bash while read -u 3 line do echo -n "Remove file $line?" read -u 1 -n 1 key [[ $key = "y" ]] && rm "$line" echo done 3<filelist 

If ANY key other than the "y" key (lower case only) is pressed, the file will not be deleted. It is not necessary to press return after the key (hence the echo command to send a new line to the display). Note that the POSIX bash "read" command does not support the -u switch so a workaround would need to be sought.

Yes default base on Dennis Williamson answer

#!/bin/bash confirm() { # call with a prompt string or use a default read -r -p "${1:-Are you sure?} [Y/n] " response case "$response" in @([nN])*([oO])) false ;; *) true ;; esac }