How to cut html tag from very large multiline text file with content with use perl, sed or awk?

Question

I want to transform this text (remove $.*?$) with sed, awk or perl:

{|
|-
| colspan=\"2\"|
: $[\backslash \backslash underbrace\{\backslash \backslash col$

Answer 1

This isn't quite the one-liner but it does what you're looking for. As always there are many ways of doing this. But here I am using '|' as the records separator and ':' as the field separator. That allows me to iterate over the fields in a record that contains math and only print the fields that don't contain $$.

BEGIN {RS="|";FS=":";ORS=""}

/math/ {
    for (i=1;i<=NF;i++) {
        if ($i ~ /math/) {print ":\n"}
        else {print $i}
    }
    print "|";next;
}

/^\}/ {
    print "}";
    next;
}

{
    print $0"|"
}

END {print "\n"}