Condition checking

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# 1  
Old 06-16-2002
Condition checking

Dear all

That's another problem from me, i wanna do a lot of if statement checking for correct input by user, will be prompt input again if the input not meet the requirement defined by If or while statement...

like this one ....

while [ $a != "a1232132" -o $a != "asdfsdaf" ....... \
$a != "basdfd" -o $a != "bj-sdf"..... ]

I know it's less effiency write the program like this if too many compare string occured, can anyone help me find a best way to solve this sort of verification....

thanks in advance!!!
# 2  
Old 06-17-2002
Here is one way...
#! /usr/bin/sh


while [ $done -eq 0 ] ; do
        echo enter value --
        read val
        case $val in
        111)  echo do 111 thing
        222)  echo do 222 thin
        333)  echo do 333 thing
              echo do more 333 stuff
        *)    done=0
              echo fumble

# 3  
Old 06-17-2002
My 2 cents here: I notice that the logical condition "a not equal dhgsf or a not equal hdhdhss or a not equal zxhcgvxhsg (etc)" is ALWAYS TRUE :-)

You probably meant -a (and) instead of -o (or) Smilie
# 4  
Old 06-17-2002
Us frog prince, Yes, that's right, should be use AND (-a) here.

HI Perderabo, you probably misunderstand what I means, ok here is a example:

echo “Please enter item name or ID: “
read name
while [ $name != “name1” -a $name != “name2” -a\ $name != “stock1” $name != “desk” -a ....... ]
# check whether have in store
echo “We have no such item!!!”
echo “ “

echo “Item name: “ $name

the question here is: if there are many many kind of items, obviously you must waster time to write long coding to include all of items you have, therefore any other methods suitable for this sort of problem?
# 5  
Old 06-17-2002
If the list is that huge you might need to go through a text file, as an input. Won't speed up the execution, though.

I can't think about something other than what Perperado already suggested:

while [[ $ok -eq 0 ]]
echo "Choice? \c" ; read choice
case $choice in
stock1) ok=1;;
desk) ok=1;;
*) ok=0;;
echo "Your choice was: $choice"
# 6  
Old 06-17-2002
Your example doesn't make sense. A "while" does not have two sections like that. You can't do stuff between the test and the "do"! It looks like you might mean to use an "if" statement? Also a "while" implies looping until something changes. It look like a legal value will give you an infinite loop. And if the user enters an illegal value, are you just going to give up? Or loop until you get a legal value?

And in any event, if there are, say, 10 strings that you must check for, then you need to check for them all. No way around that. But rather than code a lengthy "if" statement ( or "while" statement), I would go with a "case" statement.
# 7  
Old 06-17-2002
if you'd find it easier to maintain a file of products & check against that, you could do a grep & check the value of $? to see if it is in the file.


grep -x $name productfile 1>/dev/null 2>&1
if [ $? -eq 0 ]
then echo "item name :" $name
else echo "not found :" $name

the -x option limits the grep to exact matches, that is if productfile contains


the grep will only match "a123123" & would not match a name such as "a123"

Hope this helps.
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