精确匹配/子字符串

Question

I have a set of words which looks like:
fruits.txt

APPLE,2  
apple,3  
APPLE-ORANGE,3  
APPLEORANGE-GRAPE,5  

and trying to print "apples" only.

here is what i've tried and almost all the commands with similar problem return the same output as follows:
grep -iE "apple\\b" fruits.txt
APPLE,2
apple,3
APPLE-ORANGE,3 ##this is the extra line which i want to ignore

also i've tried the following, but didn't return anything.
grep -i '^apple$' fruits.txt

EXPECTED OUTPUT
APPLE,2
apples,3

PS: Please don't suggest on grep -iE 'apple\\b' fruits.txt | grep -v "-" grep -iE 'apple\\b' fruits.txt | grep -v "-" I can't use this in a loop in case of greping "APPLE-ORANGE", again It'll be a problem.

Answer 1

Try:

grep -i 'apple[ ,]' fruits.txt 
grep -iP 'apple\b(?=[\s,])' fruits.txt

from the

APPLE,2
apple,3
APPLE-ORANGE,3
APPLEORANGE-GRAPE,5
applE , 8
AAple900

both prints

APPLE,2
apple,3
applE , 8

Both regexes search for case insensitive apple followed by at least one (space) or , .

if you don't want accept (space) just remove the character groups...

Or, you should say to grep what isn't allowed to follow the apple , like:

grep -iP 'apple[^\w-]' fruits.txt
grep -iE 'apple[^[:alnum:]-]' fruits.txt

search for apple what isn't followed by any word character or - .

Answer 2

You could use awk for this task:

$ awk -F, -v IGNORECASE=1 '$1 ~ /^apple$/' fruits.txt
APPLE,2  
apple,3

If you want to pass awk a shell variable to be used, you could do this:

$ fruit=apple
$ awk -F, -v IGNORECASE=1 -v FRUIT="^$fruit\$" '$1 ~ FRUIT' fruits.txt
APPLE,2  
apple,3