CODEWITHSUNDEEP
linuxbashshellunix
user637965
user637965

Reputation:

simple bash script with if else statement plus debugging issue

I'm working on a simple bash script and no matter what the user inputs as choice, the result of the first condition is always printed. Can someone explain what's going on here? On side note, how do you go about debugging a bash script like this? When I try debugging in ecplise using the shell script plugin, the only option is an "ant build" which, when I try it, does nothing arrgggh!

if [ -f $1 ]
then
    echo "Are you sure you want to delete $1? Y for yes, N for no"
    read choice
    if [ $choice="Y" ]
    then
        echo "okay"
    else
        echo "file was not deleted"
    fi 
fi

Upvotes: 0

Views: 1558

Answers (3)

Barton Chittenden
Barton Chittenden

Reputation: 4416

In order to track the execution of your script use

set -x

This will make the shell print out the values as the interpreter sees them, line by line... however, in this case, it doesn't tell you very much:

$ cat /tmp/test.sh 
set -x
if [ -f $1 ]
then
    echo "Are you sure you want to delete $1? Y for yes, N for no"
    read choice
    if [ $choice="Y" ]
    then
        echo "okay"
    else
        echo "file was not deleted"
    fi 
fi



$ bash /tmp/test.sh 
+ '[' -f ']'
+ echo 'Are you sure you want to delete ? Y for yes, N for no'
Are you sure you want to delete ? Y for yes, N for no
+ read choice
N
+ '[' N=Y ']'
+ echo okay
okay

Well... actually, it literally tells you that '[ $choice="Y" ]' is incorrect, but it doesn't tell you why it's wrong or how to fix it.

Upvotes: 0

lc2817
lc2817

Reputation: 3742

If think you launch your script without any argument. In that case $1 refers to nothing and [ -f $1 ] is always true. Try to launch your script with an argument to figure out.

Upvotes: 0

Ignacio Vazquez-Abrams
Ignacio Vazquez-Abrams

Reputation: 798556

[ $choice="Y" ] Replaces $choice, then sees if the replacement with '="Y"' appended to it is a non-empty string. You meant [ "$choice" = Y ].

Upvotes: 2

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