In Unix, the line ending is LF (
\n), when a line is missing that, the next line is tacked to the current line at end as if they were a single line.
This is what happening here, the file
/usr/local/var/run/php-fpm.pid got a single line with the PID and the line does not end in LF, on most shells yopu would get the next prompt tacked with the output, but here
zsh is being smart and adding a
\n indicating the line is missing a LF.
foo@bar% cat /proc/self/cmdline
foo@bar$ cat /proc/self/cmdline