I just tested this myself and if you only get one process ID returned, it's the pid of the grep command you just ran since it also contains the string "LD_L1BRARY_PATH". Same happens if you type any string in case you want to test it for yourself
That's why it's exiting before you can see what it is and gives you a new pid every time, nothing to worry about if it's just one
root@TOWER:~# sudo grep -al LD_L1BRARY_PATH /proc/*/environ | grep -v self/
/proc/5098/environ
root@TOWER:~# sudo grep -al LD_L1BRARY_PATH_TEST /proc/*/environ | grep -v self/
/proc/5314/environ
root@TOWER:~# sudo grep -al HelloUnraid /proc/*/environ | grep -v self/
/proc/13914/environ
