Quicky script, adapt as you see fit:
#!/usr/bin/env bash find /project/ -name '*.pdf' -print0 | while read -d $'\0' i; do if [ ! -e "$" ]; then echo "$ doesn't exist!" fi done exit 0 -d $'\0' sets the delimiter for read to nullbyte, while -print0 is the equivalent for find, so this should be bulletproof against files with spaces and newlines in their names (obviously irrelevant in this case, but useful to know in general). $ replaces the .pdf at the end of the variable $i with -project.zip. Other than that, this is all standard shell scripting stuff.
If you wanted to shorten it even more, you could also use
[ -e "$" ] || echo "$ doesn't exist!" ...instead of the if statement. I think that if is easier to work with if you're using more than a single, short line (you can get around this by using a function, but at that point you aren't getting any psace saving vs. using the if).
Assuming you have bash 4+ (you probably do; you can check with bash --version), you can use the globstar option instead of find:
#!/usr/bin/env bash shopt -s globstar for f in /project/**/*.pdf; do if [ ! -e "$" ]; then echo "$ doesn't exist!" fi done exit 0 This has the advantage of being pure bash, so it should be faster (only noticeably so with at least hundreds of files, though).