Until the file extension matches

Shell Programming and Scripting
1

Hi All,

In my script I am trying to input data from user and I want the promt to appear again if the input data is not the one expected.

I tried something like this:

    echo " \n\n\t Enter the dump filename:\c";read dump
    pst=${dump##*.}
    until (test $pst = dmp)
        do
        echo " \n\n\t File extension not supported.!!!"
        echo " \n\n\t Enter the dump filename(eg:abc.dmp):\c"
        read dump
        done

but this not become false in any case and the prompt is apprearing again and again even if the condition is met(ie,if the user inputs .dmp file)
Where did I go wrong?

2

For string comparisons always put variables and strings in double qoutes.

like

until (test "$pst" = "dmp" )

3

Thanks Ashish..
You are rt..

4

Use two =, not one:

until (test $pst == dmp)

BTW: to get answers it's generally a good idea to write which shell you're using

5

ksh. And

is throwing the following error:

One more issue the "" worked only first time..
That is when I gave .dmp after accessing the script for the first time it goes through and comes to next step.
but when I gave .dmp again after an error it again throwed error :confused:

6

That is , If I commit a mistake once I dont get a chance to rectify the same.
Can any one please explain why is this so? Is this a property of "until"?

7

First thing is that you have a logic problem.
you're saying "until" $pst,
the you read & set dump, and then don't reset what pst is??
How would that ever work??

#!/usr/bin/ksh

print " \n\n\t Enter the dump filename:\c"; read dump
    pst=${dump##*.}

    until [ $pst = dmp ] 
    do
        print " \n\n\t File extension not supported.!!!"
        print " \n\n\t Enter the dump filename(eg:abc.dmp):\c"
        read dump
        pst=${dump##*.}
    done
8

Thanks denn.