Arch Linux: Arbitrary command execution (CVE-2022-1271)

Malicious filenames with two or more newlines can make zgrep and xzgrep to write to arbitrary files or (with a GNU sed extension) lead to arbitrary code execution. The issue with the old code is that with multiple newlines, the N-command will read the second line of input, then the s-commands will be skipped because it's not the end of the file yet, then a new sed cycle starts and the pattern space is printed and emptied. So only the last line or two get escaped.