grep -v: How to exclude only the first (or last) N lines that match?

You could use awk to ignore the first n lines that match (e.g. assuming you wanted to remove only the 1st and 2nd match from the file):

n=2
awk -v c=$n '/PATTERN/ && i++ < c {next};1' infile

---

To ignore the last n lines that match:

awk -v c=${lasttoprint} '!(/PATTERN/ && NR > c)' infile

where ${lasttoprint} is the line number of the nth+1 to last match in your file. There are various ways to get that line no. (e.g. print only the line number for each match via tools like sed/awk, then tail | head to extract it)... here's one way with gnu awk:

n=2
lasttoprint=$(gawk -v c=$((n+1)) '/PATTERN/{x[NR]};
END{asorti(x,z,"@ind_num_desc");{print z[c]}}' infile)

sed provides a simpler way:

... |  sed '/some stuff/ {N; s/^.*\n//; :p; N; $q; bp}' | ...

This way you delete first occurrence.

If you want more:

sed '1 {h; s/.*/iiii/; x}; /some stuff/ {x; s/^i//; x; td; b; :d; d}'

, where count of i is count of occurrences (one or more, not zero).

Multi-line Explanation

sed '1 {
    # Save first line in hold buffer, put `i`s to main buffer, swap buffers
    h
    s/^.*$/iiii/
    x
}

# For regexp what we finding
/some stuff/ {
    # Remove one `i` from hold buffer
    x
    s/i//
    x
    # If successful, there was `i`. Jump to `:d`, delete line
    td
    # If not, process next line (print others).
    b
    :d
    d
}'

In addition

Probably, this variant will work faster, 'cos it reads all rest lines and print them in one time

sed '1 {h; s/.*/ii/; x}; /a/ {x; s/i//; x; td; :print_all; N; $q; bprint_all; :d; d}'

As result

You can put this code into your .bashrc (or config of your shell, if it is other):

dtrash() {
    if [ $# -eq 0 ]
    then
        cat
    elif [ $# -eq 1 ]
    then
        sed "/$1/ {N; s/^.*\n//; :p; N; \$q; bp}"
    else
        count=""
        for i in $(seq $1)
        do
            count="${count}i"
        done
        sed "1 {h; s/.*/$count/; x}; /$2/ {x; s/i//; x; td; :print_all; N; \$q; bprint_all; :d; d}"

    fi
}

And use it this way:

# Remove first occurrence
cat file | dtrash 'stuff' 
# Remove four occurrences
cat file | dtrash 4 'stuff'
# Don't modify
cat file | dtrash