You can do it in more efficiently in awk: exit as soon as you've hit the relevant line.
awk 'NR==132 {if (/^#termcapinfo[[:space:]]*xterm Z0=/) found=1; exit}
END {exit !found}' /etc/screenrc
Alternatively, you can use GNU sed (but portable sed doesn't let you specify the exit code).
Alternatively, you can use the Unix philosophy of combining tools together: extract the line you want with head and tail, and pass it to grep.
</etc/screenrc tail -n +132 | head -n 1 |
grep -q '^#termcapinfo[[:space:]]*xterm Z0='
Or you can use sed to extract the desired line:
</etc/screenrc sed -n '32 {p; q;}' |
grep -q '^#termcapinfo[[:space:]]*xterm Z0='
(Both of these rely on the fact that you want the same outcome for an empty line and for a file that's too short.)
For such a small file, the fastest approach is likely to be one that uses a single tool, as the overhead of launching multiple programs will be larger than the performance gain from using special-purpose tools such as head, tail and sed. If you wanted line 132000000, starting off with tail -n 132000000+132000000 would likely be faster than anything else.
