I have a set of 100 questions. My requirement is when a user enter "yes", then question 1 should appear. If not, directly it go to question 2. Like that it should go on till 100 questions. Any lead would be appreciated.
This is what I tried, but it is failing.
#!/bin/bash
echo "Execute question1 "
select result in Yes No
do
echo "How to see apache config file"
exit
done
echo "execute question2"
select result in Yes No Cancel
do
echo "Command for listing processes"
exit
done
Thanks in advance
Here is a way to do this with an array.
#!/bin/bash
questions=(
"How to see apache config file"
"Command for listing processes"
"My hovercraft is full of eels"
)
for((q=0; q<${#questions[#]}; q++)); do
echo "Execute question $q?"
select result in Yes No; do
case $result in
Yes)
echo "${questions[q]}";;
esac
break
done
done
Using select for this seems rather clumsy, though. Perhaps just replace it with
read -p "Execute question $q? " -r result
case $result in
[Yy]*) echo "${questions[q]}";;
esac
Having just a list of questions still seems weird. With Bash 5+ you could have an associative array, or you could have a parallel array with the same indices with answers to the questions. But keeping each question and answer pair together in the source would make the most sense. Maybe loop over questions and answers and assign every other one to an answers array, and only increment the index when you have read a pair?
pairs=(
"How to see Apache config file"
"cat /etc/httpd.conf"
"Command for listing processes"
"ps"
"My hovercraft is full of what?"
"eels"
)
questions=()
answers=()
for((i=0; i<=${#pairs[#]}/2; ++i)); do
questions+=("${pairs[i*2]}")
answers+=("${pairs[1+i*2]}")
done
This ends up with two copies of everything, so if you are really strapped for memory, maybe refactor to just a for loop over the strings and get rid of the pairs array which is only useful during initialization.
Use an array of questions and loop over it, like this:
#!/bin/bash
n=1
questions=(
'How to see apache config file'
'Command for listing processes'
)
check_user_input(){
read -p "y/n " input
case $input in
[Yy]*) return 0;;
[Nn]*) return 1;;
*) check_user_input;;
esac
}
for question in "${questions[#]}"; {
echo "Execute question $n"
check_user_input && echo "$question"
((n++))
}
Here is a straight forward example. Play with it.
#!/bin/bash
echo "Type 'y' for yes, 'n' to skip or 'q' to quit and press Enter!"
for((i=1; i < 101; ++i)); do
echo 'Execute question '$i
while read user_input; do
if [[ "$user_input" = 'q' ]]; then
break 2
elif [[ "$user_input" = 'n' ]]; then
break
elif [[ $i -eq 1 ]]; then
echo 'How to see apache config file?'
break 2 # Change from "break 2" to "break" for the next question.
elif [[ $i -eq 2 ]]; then
echo 'Command for listing processes.'
break 2 # Change from "break 2" to "break" for the next question.
else
echo "Wrong input: $user_input"
echo "Type 'y' for yes, 'n' to skip or 'q' to quit and press Enter!"
fi
done
done
echo 'Finished'
I am having issues with this script and don't know exactly what is happening.
#Main Menu
clear
while [ "$input" -eq "0" ];
do
clear
#$input == 0
echo "Hello, What would you like me to do?"
echo ""
echo "1 = ALL TEH THINGZ!"
echo "2 = Find the enemy postions and villages"
echo "3 = Set the firewalls to my liking"
echo "4 = Confuse the enemy"
echo "5 = Deploy the spies!"
echo "6 = DISABLED Run the TOP SECRET STUFF! (Note password is required)"
echo "81 = Burn the bridges! (Cautian: Last Resort)"
echo "96 = Install/Update Software (locally)"
echo "97 = Install/Update Software (remotely)"
echo "98 = Update and add new Kali tools"
echo "99 = I am done with you for now"
read -p "Select an operation for me to do: " $input
I know I have the fi and end right but I am getting an error at the while [ "$input" -eq "0" ];
You'll get that message if $input is not a legal numeric expression; for instance, if it's the empty string. If you want to loop while it's 0, you should start out by setting it to 0.
input=0
while [ "$input" -eq 0 ]; do
...
done
Although you've tagged this bash; if you're actually using bash, you can also do this:
while (( input == 0 )); do
...
done
Note that shell is not Perl; the $ is not part of the variable name. It's better to think of $ as an operator that means "get the value of". The variable is input; you assign it with input=; you read into it with read input; etc. You only use $input when you want to get the value stored in the variable.
So, for instance, it doesn't make sense to do $input= or read $input unless the value stored in the input variable is a string which is the name of some other variable that you want to set the value of.
The problem is at
while [ "$input" -eq "0" ]
and you have not used the while loop closing statement done, too.
As you are comparing two strings, you should use
while [[ $input == 0 ]]; do <statements>; done
or
while [ $input = 0 ]; do <statements>; done
So your code will be:
#Main Menu
clear
echo -n "Select an operation for me to do: "
read input
while [ $input = 0 ]
do
clear
done
#$input == 0
echo "Hello, What would you like me to do?"
echo ""
echo "1 = ALL THE THINGZ!"
echo "2 = Find the enemy postions and villages"
echo "3 = Set the firewalls to my liking"
echo "4 = Confuse the enemy"
echo "5 = Deploy the spies!"
echo "6 = DISABLED Run the TOP SECRET STUFF! (Note password is required)"
echo "81 = Burn the bridges! (Cautian: Last Resort)"
echo "96 = Install/Update Software (locally)"
echo "97 = Install/Update Software (remotely)"
echo "98 = Update and add new Kali tools"
echo "99 = I am done with you for now"
exit 0
You should be using the little-appreciated select command here. Replace the : command with the appropriate action.
choices=(
'ALL TEH THINGZ!'
'Find the enemy postions and villages'
'Set the firewalls to my liking'
'Confuse the enemy'
'Deploy the spies!'
'DISABLED Run the TOP SECRET STUFF! (Note password is required)'
'Burn the bridges! (Cautian: Last Resort)'
'Install/Update Software (locally)'
'Install/Update Software (remotely)'
'Update and add new Kali tools'
'I am done with you for now'
)
PS3='Select an operation for me to do: '
echo 'Hello, What would you like me to do?'
select choice in "${choices[#]}"; do
case $choice in
'ALL TEH THINGZ!')
:
;;
'Find the enemy postions and villages')
:
;;
'Set the firewalls to my liking')
:
;;
'Confuse the enemy')
:
;;
'Deploy the spies!')
:
;;
'DISABLED Run the TOP SECRET STUFF! (Note password is required)')
:
;;
'Burn the bridges! (Cautian: Last Resort)')
:
;;
'Install/Update Software (locally)')
:
;;
'Install/Update Software (remotely)')
:
;;
'Update and add new Kali tools')
:
;;
'I am done with you for now')
break
;;
esac
done
You might want to look into using an associative array to construct a dispatch table.
-eq works on integers only.
$input and 0 should not be in quotes.
To convert $input to integer, use $((input)) instead.
You seem to be missing a done somewhere.
I want to pause input in a shell script, and prompt the user for choices.
The standard Yes, No, or Cancel type question.
How do I accomplish this in a typical bash prompt?
The simplest and most widely available method to get user input at a shell prompt is the read command. The best way to illustrate its use is a simple demonstration:
while true; do
read -p "Do you wish to install this program? " yn
case $yn in
[Yy]* ) make install; break;;
[Nn]* ) exit;;
* ) echo "Please answer yes or no.";;
esac
done
Another method, pointed out by Steven Huwig, is Bash's select command. Here is the same example using select:
echo "Do you wish to install this program?"
select yn in "Yes" "No"; do
case $yn in
Yes ) make install; break;;
No ) exit;;
esac
done
With select you don't need to sanitize the input – it displays the available choices, and you type a number corresponding to your choice. It also loops automatically, so there's no need for a while true loop to retry if they give invalid input.
Also, Léa Gris demonstrated a way to make the request language agnostic in her answer. Adapting my first example to better serve multiple languages might look like this:
set -- $(locale LC_MESSAGES)
yesexpr="$1"; noexpr="$2"; yesword="$3"; noword="$4"
while true; do
read -p "Install (${yesword} / ${noword})? " yn
if [[ "$yn" =~ $yesexpr ]]; then make install; exit; fi
if [[ "$yn" =~ $noexpr ]]; then exit; fi
echo "Answer ${yesword} / ${noword}."
done
Obviously other communication strings remain untranslated here (Install, Answer) which would need to be addressed in a more fully completed translation, but even a partial translation would be helpful in many cases.
Finally, please check out the excellent answer by F. Hauri.
At least five answers for one generic question.
Depending on
posix compliant: could work on poor systems with generic shell environments
bash specific: using so called bashisms
and if you want
simple ``in line'' question / answer (generic solutions)
pretty formatted interfaces, like ncurses or more graphical using libgtk or libqt...
use powerful readline history capability
1. POSIX generic solutions
You could use the read command, followed by if ... then ... else:
printf 'Is this a good question (y/n)? '
read answer
# if echo "$answer" | grep -iq "^y" ;then
if [ "$answer" != "${answer#[Yy]}" ] ;then # this grammar (the #[] operator) means that the variable $answer where any Y or y in 1st position will be dropped if they exist.
echo Yes
else
echo No
fi
(Thanks to Adam Katz's comment: Replaced the test above with one that is more portable and avoids one fork:)
POSIX, but single key feature
But if you don't want the user to have to hit Return, you could write:
(Edited: As #JonathanLeffler rightly suggest, saving stty's configuration could be better than simply force them to sane.)
printf 'Is this a good question (y/n)? '
old_stty_cfg=$(stty -g)
stty raw -echo ; answer=$(head -c 1) ; stty $old_stty_cfg # Careful playing with stty
if [ "$answer" != "${answer#[Yy]}" ];then
echo Yes
else
echo No
fi
Note: This was tested under sh, bash, ksh, dash and busybox!
Same, but waiting explicitly for y or n:
#/bin/sh
printf 'Is this a good question (y/n)? '
old_stty_cfg=$(stty -g)
stty raw -echo
answer=$( while ! head -c 1 | grep -i '[ny]' ;do true ;done )
stty $old_stty_cfg
if [ "$answer" != "${answer#[Yy]}" ];then
echo Yes
else
echo No
fi
Using dedicated tools
There are many tools which were built using libncurses, libgtk, libqt or other graphical libraries. For example, using whiptail:
if whiptail --yesno "Is this a good question" 20 60 ;then
echo Yes
else
echo No
fi
Depending on your system, you may need to replace whiptail with another similiar tool:
dialog --yesno "Is this a good question" 20 60 && echo Yes
gdialog --yesno "Is this a good question" 20 60 && echo Yes
kdialog --yesno "Is this a good question" 20 60 && echo Yes
where 20 is height of dialog box in number of lines and 60 is width of the dialog box. These tools all have near same syntax.
DIALOG=whiptail
if [ -x /usr/bin/gdialog ] ;then DIALOG=gdialog ; fi
if [ -x /usr/bin/xdialog ] ;then DIALOG=xdialog ; fi
...
$DIALOG --yesno ...
2. Bash specific solutions
Basic in line method
read -p "Is this a good question (y/n)? " answer
case ${answer:0:1} in
y|Y )
echo Yes
;;
* )
echo No
;;
esac
I prefer to use case so I could even test for yes | ja | si | oui if needed...
in line with single key feature
Under bash, we can specify the length of intended input for for the read command:
read -n 1 -p "Is this a good question (y/n)? " answer
Under bash, read command accepts a timeout parameter, which could be useful.
read -t 3 -n 1 -p "Is this a good question (Y/n)? " answer
[ -z "$answer" ] && answer="Yes" # if 'yes' have to be default choice
Timeout with countdown:
i=6 ;while ((i-->1)) &&
! read -sn 1 -t 1 -p $'\rIs this a good question (Y/n)? '$i$'..\e[3D' answer;do
:;done ;[[ $answer == [nN] ]] && answer=No || answer=Yes ;echo "$answer "
3. Some tricks for dedicated tools
More sophisticated dialog boxes, beyond simple yes - no purposes:
dialog --menu "Is this a good question" 20 60 12 y Yes n No m Maybe
Progress bar:
dialog --gauge "Filling the tank" 20 60 0 < <(
for i in {1..100};do
printf "XXX\n%d\n%(%a %b %T)T progress: %d\nXXX\n" $i -1 $i
sleep .033
done
)
Little demo:
#!/bin/sh
while true ;do
[ -x "$(which ${DIALOG%% *})" ] || DIALOG=dialog
DIALOG=$($DIALOG --menu "Which tool for next run?" 20 60 12 2>&1 \
whiptail "dialog boxes from shell scripts" >/dev/tty \
dialog "dialog boxes from shell with ncurses" \
gdialog "dialog boxes from shell with Gtk" \
kdialog "dialog boxes from shell with Kde" ) || break
clear;echo "Choosed: $DIALOG."
for i in `seq 1 100`;do
date +"`printf "XXX\n%d\n%%a %%b %%T progress: %d\nXXX\n" $i $i`"
sleep .0125
done | $DIALOG --gauge "Filling the tank" 20 60 0
$DIALOG --infobox "This is a simple info box\n\nNo action required" 20 60
sleep 3
if $DIALOG --yesno "Do you like this demo?" 20 60 ;then
AnsYesNo=Yes; else AnsYesNo=No; fi
AnsInput=$($DIALOG --inputbox "A text:" 20 60 "Text here..." 2>&1 >/dev/tty)
AnsPass=$($DIALOG --passwordbox "A secret:" 20 60 "First..." 2>&1 >/dev/tty)
$DIALOG --textbox /etc/motd 20 60
AnsCkLst=$($DIALOG --checklist "Check some..." 20 60 12 \
Correct "This demo is useful" off \
Fun "This demo is nice" off \
Strong "This demo is complex" on 2>&1 >/dev/tty)
AnsRadio=$($DIALOG --radiolist "I will:" 20 60 12 \
" -1" "Downgrade this answer" off \
" 0" "Not do anything" on \
" +1" "Upgrade this anser" off 2>&1 >/dev/tty)
out="Your answers:\nLike: $AnsYesNo\nInput: $AnsInput\nSecret: $AnsPass"
$DIALOG --msgbox "$out\nAttribs: $AnsCkLst\nNote: $AnsRadio" 20 60
done
More samples? Have a look at Using whiptail for choosing USB device and USB removable storage selector: USBKeyChooser
5. Using readline's history
Example:
#!/bin/bash
set -i
HISTFILE=~/.myscript.history
history -c
history -r
myread() {
read -e -p '> ' $1
history -s ${!1}
}
trap 'history -a;exit' 0 1 2 3 6
while myread line;do
case ${line%% *} in
exit ) break ;;
* ) echo "Doing something with '$line'" ;;
esac
done
This will create a file .myscript.history in your $HOME directory, than you could use readline's history commands, like Up, Down, Ctrl+r and others.
echo "Please enter some input: "
read input_variable
echo "You entered: $input_variable"
You can use the built-in read command ; Use the -p option to prompt the user with a question.
Since BASH4, you can now use -i to suggest an answer :
read -e -p "Enter the path to the file: " -i "/usr/local/etc/" FILEPATH
echo $FILEPATH
(But remember to use the "readline" option -e to allow line editing with arrow keys)
If you want a "yes / no" logic, you can do something like this:
read -e -p "
List the content of your home dir ? [Y/n] " YN
[[ $YN == "y" || $YN == "Y" || $YN == "" ]] && ls -la ~/
Bash has select for this purpose. Here's how you would use it in a script:
select result in Yes No Cancel
do
echo $result
done
This is what it would look like to use:
$ bash examplescript.sh
1) Yes
2) No
3) Cancel
#? 1
Yes
#? 2
No
#? 3
Cancel
#?
read -p "Are you alright? (y/n) " RESP
if [ "$RESP" = "y" ]; then
echo "Glad to hear it"
else
echo "You need more bash programming"
fi
inquire () {
echo -n "$1 [y/n]? "
read answer
finish="-1"
while [ "$finish" = '-1' ]
do
finish="1"
if [ "$answer" = '' ];
then
answer=""
else
case $answer in
y | Y | yes | YES ) answer="y";;
n | N | no | NO ) answer="n";;
*) finish="-1";
echo -n 'Invalid response -- please reenter:';
read answer;;
esac
fi
done
}
... other stuff
inquire "Install now?"
...
Here's something I put together:
#!/bin/sh
promptyn () {
while true; do
read -p "$1 " yn
case $yn in
[Yy]* ) return 0;;
[Nn]* ) return 1;;
* ) echo "Please answer yes or no.";;
esac
done
}
if promptyn "is the sky blue?"; then
echo "yes"
else
echo "no"
fi
I'm a beginner, so take this with a grain of salt, but it seems to work.
You want:
Bash builtin commands (i.e. portable)
Check TTY
Default answer
Timeout
Colored question
Snippet
do_xxxx=y # In batch mode => Default is Yes
[[ -t 0 ]] && # If TTY => Prompt the question
read -n 1 -p $'\e[1;32m
Do xxxx? (Y/n)\e[0m ' do_xxxx # Store the answer in $do_xxxx
if [[ $do_xxxx =~ ^(y|Y|)$ ]] # Do if 'y' or 'Y' or empty
then
xxxx
fi
Explanations
[[ -t 0 ]] && read ... => Call command read if TTY
read -n 1 => Wait for one character
$'\e[1;32m ... \e[0m ' => Print in green
(green is fine because readable on both white/black backgrounds)
[[ $do_xxxx =~ ^(y|Y|)$ ]] => bash regex
Timeout => Default answer is No
do_xxxx=y
[[ -t 0 ]] && { # Timeout 5 seconds (read -t 5)
read -t 5 -n 1 -p $'\e[1;32m
Do xxxx? (Y/n)\e[0m ' do_xxxx || # read 'fails' on timeout
do_xxxx=n ; } # Timeout => answer No
if [[ $do_xxxx =~ ^(y|Y|)$ ]]
then
xxxx
fi
The easiest way to achieve this with the least number of lines is as follows:
read -p "<Your Friendly Message here> : y/n/cancel" CONDITION;
if [ "$CONDITION" == "y" ]; then
# do something here!
fi
The if is just an example: it is up to you how to handle this variable.
Use the read command:
echo Would you like to install? "(Y or N)"
read x
# now check if $x is "y"
if [ "$x" = "y" ]; then
# do something here!
fi
and then all of the other stuff you need
This solution reads a single character and calls a function on a yes response.
read -p "Are you sure? (y/n) " -n 1
echo
if [[ $REPLY =~ ^[Yy]$ ]]; then
do_something
fi
It is possible to handle a locale-aware "Yes / No choice" in a POSIX shell; by using the entries of the LC_MESSAGES locale category, witch provides ready-made RegEx patterns to match an input, and strings for localized Yes No.
#!/usr/bin/env sh
# Getting LC_MESSAGES values into variables
# shellcheck disable=SC2046 # Intended IFS splitting
IFS='
' set -- $(locale LC_MESSAGES)
yesexpr="$1"
noexpr="$2"
yesstr="$3"
nostr="$4"
messages_codeset="$5" # unused here, but kept as documentation
# Display Yes / No ? prompt into locale
echo "$yesstr / $nostr ?"
# Read answer
read -r yn
# Test answer
case "$yn" in
# match only work with the character class from the expression
${yesexpr##^}) echo "answer $yesstr" ;;
${noexpr##^}) echo "answer $nostr" ;;
esac
EDIT:
As #Urhixidur mentioned in his comment:
Unfortunately, POSIX only specifies the first two (yesexpr and noexpr). On Ubuntu 16, yesstr and nostr are empty.
See: https://www.ee.ryerson.ca/~courses/ele709/susv4/xrat/V4_xbd_chap07.html#tag_21_07_03_06
LC_MESSAGES
The yesstr and nostr locale keywords and the YESSTR and NOSTR langinfo items were formerly used to match user affirmative and negative responses. In POSIX.1-2008, the yesexpr, noexpr, YESEXPR, and NOEXPR extended regular expressions have replaced them. Applications should use the general locale-based messaging facilities to issue prompting messages which include sample desired responses.
Alternatively using locales the Bash way:
#!/usr/bin/env bash
IFS=$'\n' read -r -d '' yesexpr noexpr _ < <(locale LC_MESSAGES)
printf -v yes_or_no_regex "(%s)|(%s)" "$yesexpr" "$noexpr"
printf -v prompt $"Please answer Yes (%s) or No (%s): " "$yesexpr" "$noexpr"
declare -- answer=;
until [[ "$answer" =~ $yes_or_no_regex ]]; do
read -rp "$prompt" answer
done
if [[ -n "${BASH_REMATCH[1]}" ]]; then
echo $"You answered: Yes"
else
echo $"No, was your answer."
fi
The answer is matched using locale environment's provided regexps.
To translate the remaining messages, use bash --dump-po-strings scriptname to output the po strings for localization:
#: scriptname:8
msgid "Please answer Yes (%s) or No (%s): "
msgstr ""
#: scriptname:17
msgid "You answered: Yes"
msgstr ""
#: scriptname:19
msgid "No, was your answer."
msgstr ""
To get a nice ncurses-like inputbox use the command dialog like this:
#!/bin/bash
if (dialog --title "Message" --yesno "Want to do something risky?" 6 25)
# message box will have the size 25x6 characters
then
echo "Let's do something risky"
# do something risky
else
echo "Let's stay boring"
fi
The dialog package is installed by default at least with SUSE Linux. Looks like:
In my case I needed to read from a downloaded script i.e.,
curl -Ss https://example.com/installer.sh | sh
The line read -r yn </dev/tty allowed it to read input in this case.
printf "These files will be uploaded. Is this ok? (y/N) "
read -r yn </dev/tty
if [ "$yn" = "y" ]; then
# Yes
else
# No
fi
Single keypress only
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 [y/n]? "
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 $?
1
Here, 1 or false was returned. Note that with this lower-level function you'll need to provide your own [y/n]? prompt.
Code
# Read a single char from /dev/tty, prompting with "$*"
# 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
}
You can use the default REPLY on a read, convert to lowercase and compare to a set of variables with an expression.
The script also supports ja/si/oui
read -rp "Do you want a demo? [y/n/c] "
[[ ${REPLY,,} =~ ^(c|cancel)$ ]] && { echo "Selected Cancel"; exit 1; }
if [[ ${REPLY,,} =~ ^(y|yes|j|ja|s|si|o|oui)$ ]]; then
echo "Positive"
fi
read -e -p "Enter your choice: " choice
The -e option enables the user to edit the input using arrow keys.
If you want to use a suggestion as input:
read -e -i "yes" -p "Enter your choice: " choice
-i option prints a suggestive input.
Lots of good answers to this question, but from what I can see none of them are my ideal, which would:
Be simple, just a couple lines of shell
Work with a single y/n keypress (no need to press enter)
Default to yes if you just hit enter
Work with an uppercase Y/N as well
Here's my version which does has those properties:
read -n1 -p "Continue? (Y/n) " confirm
if ! echo $confirm | grep '^[Yy]\?$'; then
exit 1
fi
You can modify that conditional to only run on "yes" (just remove the ! in the if statement) or add an else if you want to run code on both branches.
One-liner:
read -p "Continue? [Enter] → Yes, [Ctrl]+[C] → No."
This assumes that "No" and "Cancel" have the same outcome, so no reason to treat them differently.
I noticed that no one posted an answer showing multi-line echo menu for such simple user input so here is my go at it:
#!/bin/bash
function ask_user() {
echo -e "
#~~~~~~~~~~~~#
| 1.) Yes |
| 2.) No |
| 3.) Quit |
#~~~~~~~~~~~~#\n"
read -e -p "Select 1: " choice
if [ "$choice" == "1" ]; then
do_something
elif [ "$choice" == "2" ]; then
do_something_else
elif [ "$choice" == "3" ]; then
clear && exit 0
else
echo "Please select 1, 2, or 3." && sleep 3
clear && ask_user
fi
}
ask_user
This method was posted in the hopes that someone may find it useful and time-saving.
Check this
read -p "Continue? (y/n): " confirm && [[ $confirm == [yY] || $confirm == [yY][eE][sS] ]] || exit 1
Multiple choice version:
ask () { # $1=question $2=options
# set REPLY
# options: x=..|y=..
while $(true); do
printf '%s [%s] ' "$1" "$2"
stty cbreak
REPLY=$(dd if=/dev/tty bs=1 count=1 2> /dev/null)
stty -cbreak
test "$REPLY" != "$(printf '\n')" && printf '\n'
(
IFS='|'
for o in $2; do
if [ "$REPLY" = "${o%%=*}" ]; then
printf '\n'
break
fi
done
) | grep ^ > /dev/null && return
done
}
Example:
$ ask 'continue?' 'y=yes|n=no|m=maybe'
continue? [y=yes|n=no|m=maybe] g
continue? [y=yes|n=no|m=maybe] k
continue? [y=yes|n=no|m=maybe] y
$
It will set REPLY to y (inside the script).
Inspired by the answers of #Mark and #Myrddin I created this function for a universal prompt
uniprompt(){
while true; do
echo -e "$1\c"
read opt
array=($2)
case "${array[#]}" in *"$opt"*) eval "$3=$opt";return 0;; esac
echo -e "$opt is not a correct value\n"
done
}
use it like this:
unipromtp "Select an option: (a)-Do one (x)->Do two (f)->Do three : " "a x f" selection
echo "$selection"
I suggest you use dialog...
Linux Apprentice: Improve Bash Shell Scripts Using Dialog
The dialog command enables the use of window boxes in shell scripts to make their use more interactive.
it's simple and easy to use, there's also a gnome version called gdialog that takes the exact same parameters, but shows it GUI style on X.
more generic would be:
function menu(){
title="Question time"
prompt="Select:"
options=("Yes" "No" "Maybe")
echo "$title"
PS3="$prompt"
select opt in "${options[#]}" "Quit/Cancel"; do
case "$REPLY" in
1 ) echo "You picked $opt which is option $REPLY";;
2 ) echo "You picked $opt which is option $REPLY";;
3 ) echo "You picked $opt which is option $REPLY";;
$(( ${#options[#]}+1 )) ) clear; echo "Goodbye!"; exit;;
*) echo "Invalid option. Try another one.";continue;;
esac
done
return
}
yn() {
if [[ 'y' == `read -s -n 1 -p "[y/n]: " Y; echo $Y` ]];
then eval $1;
else eval $2;
fi }
yn 'echo yes' 'echo no'
yn 'echo absent no function works too!'
One simple way to do this is with xargs -p or gnu parallel --interactive.
I like the behavior of xargs a little better for this because it executes each command immediately after the prompt like other interactive unix commands, rather than collecting the yesses to run at the end. (You can Ctrl-C after you get through the ones you wanted.)
e.g.,
echo *.xml | xargs -p -n 1 -J {} mv {} backup/
As a friend of a one line command I used the following:
while [ -z $prompt ]; do read -p "Continue (y/n)?" choice;case "$choice" in y|Y ) prompt=true; break;; n|N ) exit 0;; esac; done; prompt=;
Written longform, it works like this:
while [ -z $prompt ];
do read -p "Continue (y/n)?" choice;
case "$choice" in
y|Y ) prompt=true; break;;
n|N ) exit 0;;
esac;
done;
prompt=;
I've used the case statement a couple of times in such a scenario, using the case statment is a good way to go about it. A while loop, that ecapsulates the case block, that utilizes a boolean condition can be implemented in order to hold even more control of the program, and fulfill many other requirements. After the all the conditions have been met, a break can be used which will pass control back to the main part of the program. Also, to meet other conditions, of course conditional statements can be added to accompany the control structures: case statement and possible while loop.
Example of using a case statement to fulfill your request
#! /bin/sh
# For potential users of BSD, or other systems who do not
# have a bash binary located in /bin the script will be directed to
# a bourne-shell, e.g. /bin/sh
# NOTE: It would seem best for handling user entry errors or
# exceptions, to put the decision required by the input
# of the prompt in a case statement (case control structure),
echo Would you like us to perform the option: "(Y|N)"
read inPut
case $inPut in
# echoing a command encapsulated by
# backticks (``) executes the command
"Y") echo `Do something crazy`
;;
# depending on the scenario, execute the other option
# or leave as default
"N") echo `execute another option`
;;
esac
exit