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Bash user input

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# 1  
Old 03-31-2010
Bash user input
Hi all, I currently have a script which uses read -p for user interaction. e.g.

Code:
read -p "New user? " user

Is it possible to have it so if the user enters nothing and just presses return it can resort to a specified value instead?

Thanks! Smilie
JayC89
# 2  
Old 03-31-2010
Code:
read -p "New user? " user

if [ "$user" == "" ]
then
echo "assign default value"
user=Default
else
echo "Ok"

fi

# 3  
Old 03-31-2010
Thank you for the prompt reply amitranjansahu, that worked a treat! Smilie

I'm also trying to get the script to accept varriables from the command line instead of running it and being prompted for the answers for example, instead of;

Code:
./test.sh
Whats the username:

I could just type

Code:
./test.sh username

And if the script isnt ran with the variables appended it still asks as it does at the moment.

Is that possible?
JayC89
# 4  
Old 03-31-2010
Code:
# Is there a parameter on the command line?
# If not then ask for the parameter. 
if [ ! "$1""X" = "X" ]
then
        user="$1"
else
        read -p "New user? " user
fi
#
if [ "${user}" == "" ]
then
        echo "assign default value"
        user="Default"
else
        echo "Ok"
fi

Last edited by methyl; 03-31-2010 at 09:24 AM..
# 5  
Old 03-31-2010
Quote:
Originally Posted by amitranjansahu
Code:
read -p "New user? " user

if [ "$user" == "" ]
then
echo "assign default value"
user=Default
else
echo "Ok"

fi

Alternatively, you can simply use $user in the following way:
Code:
${user:-default_value}

That will return the value of $user if it is set and not null; otherwise, it will return "default_value".

Regards,
Alister
# 6  
Old 03-31-2010
Code:
user="$1"   # take arg
# if empty then ask
[ "$user" = "" ] && read -p "New user? " user
# if value is empty, set some default
[ "$user" = "" ] && user="somedefaultvalue"

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