I'm trying to get this script to loop back and restart if the user inputs a response that does not match the choices allowed but then enters a correct response the second time around. I tried using continue, but it loops infinitely. Any thoughts?
`
#!/bin/bash
#Obtaing user selection and input
echo " Gathering list of users on this machine..."
sleep 2
echo "$( ls /Users )"
echo "From the list above, which user did you want to work with?"
read userSelection
echo "What is that user's password?"
#Hiding User's Password
stty -echo
read userSelectionPassword
stty echo
echo "Did you want [enable], [disable], or check the current [status] of Secure Token for $userSelection?"
read taskSelection
#Converting input to lowercase
taskSelectionLower=$(echo $taskSelection | tr '[:upper:]' '[:lower:]')
#Running commands
while [ true ]
do
if [[ $taskSelectionLower == "enable" ]]; then
echo "Enabling..."
echo "$(sysadminctl -adminUser AdminUser -adminPassword AdminPass -secureTokenOn $userSelection -password $userSelectionPassword)"
break
elif [[ $taskSelectionLower == "status" ]]; then
echo "Displaying $userSelection current Secure Token status..."
echo "$( sysadminctl -secureTokenStatus $userSelection )"
break
elif [[ $taskSelectionLower == "disable" ]]; then
echo "Disabling..."
echo "$(sysadminctl -adminUser AdminUser -adminPassword AdminPass -secureTokenOff $userSelection -password $userSelectionPassword)"
break
else
echo "Incorrect selection made..."
echo "Did you want [enable], [disable], or check the current [status] of Secure Token for $userSelection?"
read taskSelection
exit
fi
done
`
Attempted using continue at the end of the condition, but loops infinitely.
Expected outcome would be for the for loop to restart, allowing the user to input a correct response and get the correct output.
The select command was designed exactly for this sort of interactive script.
Some hopefully useful observations -
echo " Gathering list of users on this machine..."
sleep 2 # why?
This sleep seems to serve no purpose but to annoy the user.
echo "$( ls /Users )" # why?? Don't do this.
This is exactly the same as
ls /Users # same output. Keep it simple.
Also, since you are bash instead of sh, rather than
taskSelectionLower=$(echo $taskSelection | tr '[:upper:]' '[:lower:]')
try declaring the variable as lowercase -
declare -l taskSelectionLower
read taskSelectionLower
or handle it with parameter parsing syntax -
read taskSelectionLower
taskSelectionLower="${taskSelectionLower,,}"
but why let them possibly mistype at all?
Consider using a select statement.
Rather than building your own loop, presenting options, worrying about formatting, etc, let tools that already do that handle it for you.
My rewrite using echo to show the commands to be executed - take those out and it should run fine.
#!/bin/bash
cd /c/Users
echo "Please select a valid user from this system."
select u in */; do
if [[ -d "$u" ]]
then userSelection="${u%/}"; break
else echo "Please enter a number from the presented options."
fi
done # get just the username
cd $OLDPWD # if needed
admSet() { # no reason to ask for the password just to get status...
read -sp "what's $userSelection's password? " userSelectionPassword
echo # reading the password leaves the cursor on the previous line
echo sysadminctl -adminUser AdminUser -adminPassword AdminPass \
-secureToken$1 "$userSelection" -password "$userSelectionPassword"
}
select taskSelection in enable disable status; do # case is controlled
case "$taskSelection" in
status) echo "Displaying $userSelection current Secure Token status..."
echo sysadminctl -secureTokenStatus $userSelection ;;
enable) echo "Enabling..." ; admSet On ;;
disable) echo "Disabling..." ; admSet Off ;;
*) echo "Please enter a number from the presented options."
continue ;;
esac
break
done
In this particular case, I'd like to add a confirm in Bash for
Are you sure? [Y/n]
for Mercurial's hg push ssh://username#www.example.com//somepath/morepath, which is actually an alias. Is there a standard command that can be added to the alias to achieve it?
The reason is that hg push and hg out can sound similar and sometimes when I want hgoutrepo, I may accidentlly type hgpushrepo (both are aliases).
Update: if it can be something like a built-in command with another command, such as: confirm && hg push ssh://... that'd be great... just a command that can ask for a yes or no and continue with the rest if yes.
These are more compact and versatile forms of Hamish's answer. They handle any mixture of upper and lower case letters:
read -r -p "Are you sure? [y/N] " response
case "$response" in
[yY][eE][sS]|[yY])
do_something
;;
*)
do_something_else
;;
esac
Or, for Bash >= version 3.2:
read -r -p "Are you sure? [y/N] " response
if [[ "$response" =~ ^([yY][eE][sS]|[yY])$ ]]
then
do_something
else
do_something_else
fi
Note: If $response is an empty string, it will give an error. To fix, simply add quotation marks: "$response". – Always use double quotes in variables containing strings (e.g.: prefer to use "$#" instead $#).
Or, Bash 4.x:
read -r -p "Are you sure? [y/N] " response
response=${response,,} # tolower
if [[ "$response" =~ ^(yes|y)$ ]]
...
Edit:
In response to your edit, here's how you'd create and use a confirm command based on the first version in my answer (it would work similarly with the other two):
confirm() {
# call with a prompt string or use a default
read -r -p "${1:-Are you sure? [y/N]} " response
case "$response" in
[yY][eE][sS]|[yY])
true
;;
*)
false
;;
esac
}
To use this function:
confirm && hg push ssh://..
or
confirm "Would you really like to do a push?" && hg push ssh://..
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://username#www.example.com//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)
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
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
}
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:
use local to prevent variable names from colliding
read use $2 $3 ... to control its action, so you may use -n and -t
if read exits unsuccessfully, echo a line feed for beauty
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).
use IPython-style "(y/[n])" to clearly indicate that "n" is the default.
This version allows you to have more than one case y or Y, n or N
Optionally: Repeat the question until an approve question is provided
Optionally: Ignore any other answer
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 $i read.
Below code is combining two things
shopt -s nocasematch that will take care of case insensitive
and if condition that will accept both the input either you pass yes,Yes,YES,y.
shopt -s nocasematch
if [[ sed-4.2.2.$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
}
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' ] && [ $reply != 'y' ] && echo 'Aborting' && exit 1
echo 'Scary thing'
The other answers have the background on that -n1 flag and other options for read. The echo '' in the 2nd variant is to make subsequent output appear on a new line since the user doesn't have to press Return, so no newline has been echoed to the terminal.
I am trying to make a shell script that works as an ordering system. I have started with the first steps but it does not take the input I am not sure of what I am doing wrong. I have attached an image of what end result should be. What is the next step I should take and what should I begin to research
#!/bin/bash
clear
echo "orderBeds"
read -p "Please Enter you choice (Quit/Order)" order
if [$order -e Order|order]
then
echo "Please enter you name?"
elif [$order -e Quit|quit]
then
exit
fi
done
I'll start giving some general advice.
1) [ is a command. That means you probably don't want to expand a variable just next to it without separating them with white spaces.
2) If you will check against more than one option, use the case construct. Apart from giving you the chance of a better structure, you'll be able to use globbing expressions as options to match against.
That said, let's rewrite your code:
#! /bin/bash
clear
echo "orderBeds"
read -p "Please Enter your choice (Quit/Order)" order
case "$order" in
[Oo]rder)
read -p "Please enter your name: " name
echo "$name placed an order."
break
;;
[Qq]uit)
exit
;;
esac
the -e flag is for numerical equivalency.
Here is a corrected bash script to get you started:
#!/bin/bash
clear
echo "orderBeds"
read -p "Please enter your choice (Quit/Order) " order
if [ $order == "order" ] || [ $order == "Order" ]
then
read -p "Please enter your name " name
echo "$name placed an order"
elif [ $order == "quit"] || [ $order == "Quit" ]
then
exit
fi
Note the use of == instead of -e and the separation of the or clauses.
In my program, I have to check whether a command given as a input by a user exists or not and if it exists, program needs to check if the parameters of that command are correct.
For example:
ls ( is correct)
-al (is correct)
do the watch
and if I do this:
ls (is correct)
-kala (not correct)
don't do the watch.
How I can do this? Here is my script:
while true
do
echo "Insert the command"
read comm
if [ "$(type -t $comm)" != "" ]; then
echo "Insert the parameters of the command ";
read par;
echo "Insert the time of watch";
read time;
if [ $t -le 0 ]; then
echo "Value not correct";
else
clear;
while true
do
echo "$comm"
date
echo ""
$comm $par
sleep $((time))
clear
done
fi;
else
echo "Command not found, retry.";
echo "";
fi
done
You can replace the command invocation with this:
if ! $comm $par; then
exit 1
fi
to make it stop after an error. Also there is already a tool called watch but I think you already know this.
First post. Thanks in advance for all of your help.
This is a basic script I am trying to write which will change a CentOS system's DNS settings (/etc/resolv.conf). The script should do the following:
Get DNS1
Ask if there is another DNS
If yes, move to #3 (get DNS2)
If no, write '/etc/resolv.conf' with only a single DNS entry.
Get DNS2
Ask if there is another DNS
If yes, move to #5 (get DNS3)
If no, write '/etc/resolv.conf' with only two DNS entries.
Get DNS3
echo DNS1 DNS2 DNS3, and ask if they are correct
If yes, write '/etc/resolv.conf' with all three DNS entries.
If no, start over. (this part isn't written yet)
This script properly get's DNS1, asks if there is another DNS. If no, it properly writes the file. If no, it moves on to ask for DNS2.
Here is where it no longer works. After it reads DNS2, it does not continue on with the script to prompt if there is an additional DNS. It just freezes. Please let me know if you can see the fault in this process.
#
#!/bin/bash
# FUNCTION TO GRAB THE FIRST DNS
oneDNS()
{
read -p "Enter DNS: (looks like 123.231.132.1) " firstDNS
}
# FUNCTION TO GRAB THE SECOND DNS
twoDNS()
{
read -p "Enter second DNS: (looks like 123.231.132.2) " secondDNS
}
# FUNCTION TO GRAB THE THIRD DNS
threeDNS()
{
read -p "Enter third DNS: (looks like 123.321.132.3) " thirdDNS
}
# FUNCTION WHICH WRITE /etc/resolv.conf IF ONLY
writeOneResolveFile()
{
cat << EOF > $1
nameserver $firstDNS
EOF
#don't use any space before of after 'EOF' in the previous line
echo ""
echo "Your informatons was saved in '$1' file."
echo ""
exit 0
}
writeTwoResolveFile()
{
cat << EOF > $1
nameserver $firstDNS
nameserver $secondDNS
EOF
#don't use any space before of after 'EOF' in the previous line
echo ""
echo "Your informatons was saved in '$1' file."
echo ""
exit 0
}
writeThreeResolveFile()
{
cat << EOF > $1
nameserver $firstDNS
nameserver $secondDNS
nameserver $thirdDNS
EOF
#don't use any space before of after 'EOF' in the previous line
echo ""
echo "Your information was saved in '$1' file."
echo ""
exit 0
}
file="/etc/resolv.conf"
if [ ! -f $file ]; then
echo ""
echo "The file '$file' doesn't exist!"
echo ""
exit 1
fi
clear
echo "Let's set up the DNS your server"
echo ""
oneDNS
echo ""
echo "So DNS settings are:"
echo "DNS Address is: $firstDNS"
echo "Do you have another DNS? [y/n]: "
while true; do
read yn
case $yn in
[Yy]* ) twoDNS;;
[Nn]* ) writeOneResolveFile $file;;
* ) echo "Please enter y or n!";;
esac
done
echo ""
echo "So DNS settings are:"
echo "First DNS Address is: $firstDNS"
echo "Second DNS Address is: $secondDNS"
echo "Do you have another DNS? [y/n]: "
while true; do
read yn
case $yn in
[Yy]* ) threeDNS;;
[Nn]* ) writeTwoResolveFile $file;;
* ) echo "Please enter y or n!";;
esac
done
echo ""
echo "So DNS settings are:"
echo "First DNS Address is: $firstDNS"
echo "Second DNS Address is: $secondDNS"
echo "Third DNS Address is: $thirdDNS"
echo "Is this information correct? [y/n]: "
while true; do
read yn
case $yn in
[Yy]* ) writeThreeResolveFile $file;;
[Nn]* ) ;;
* ) echo "Please enter y or n!";;
esac
done
#
Again, any help is greatly appreciated.
Thanks.
Kamran
check your quotation marks carefully, you're missing one at the end of line 93.
The problem is that after asking for "oneDNS" you enter a endless loop in which you ask for "twoDNS". From this loop you never escape.
Try it out for yourself:
You might want to change your first line to #!/bin/bash -x for debug mode.
echo ""
oneDNS
echo ""
echo "So DNS settings are:"
echo "DNS Address is: $firstDNS"
echo "Do you have another DNS? [y/n]: "
while true; do #<-- how are you planning to escape from this ??
read yn
case $yn in
[Yy]* ) twoDNS;; #<-- this will be asked over and over again
[Nn]* ) writeOneResolveFile $file;;
* ) echo "Please enter y or n!";;
esac
done
Your loops have while true and nothing to break out of the endless loop. You need to specify an exit condition. The way things are, it's just asking for the yn prompt again (the second and subsequent times without any prompt).
A better design might be something like
servers=
another=true
while $another; do
read -p "DNS server address to add?" server
servers="$servers $server"
case $dns in
'') ;;
*) while true; do
read -p "Add another [yn]?" yn
case $yn in [Yy]*) break;; [Nn]*) another=false; break;; esac
done ;;
esac
done
for s in $servers; do
echo nameserver $s
done >/etc/resolv.conf
(Untested, but should hopefully at least suggest some changes.)