Question

I have tried stuff like =~ "\[[A-Za-z0-9]+\]" which I would expect would work but doesnt. I also tried "[[A-Za-z0-9]+]" and "\[[:alnum:]+\]". What am I doing wrong? Sample line I want to match: [RTNUT18] (I am iterating through a file, some lines are of this form)

This is my code snippet:

while read line;
do
    if [[ $line =~ "^\[[A-Za-z0-9]+\]$" ]]; then
        echo match
    else
        echo no match
    fi
done < $1

This is a sample file:

[RBPAT7]
Whatever=foo,bla
Otherline
RRR

and I run:

./script.sh thefile.txt

I am not getting a hit on the [RBPAT7] line at all

Answer 1

Stuff like that isn’t enough. You must use it in [[.

$ [[ [foo] =~ ^\[[A-Za-z0-9]+\]$ ]] ; echo $?
0

EDIT:

Unlike test, [[ does not need quotes around its arguments. Your code matches nothing, since you can’t have " before the beginning of the line, nor " after the end. Remove the quotes.