A few years ago I wrote a tool, mgrep, for searching Maple repositories; download mgrep.zip. The zip file includes the noweb source (mgrep.nw), however, it is missing some of the files needed to rebuild the documentation—I will add them later when I bring an old drive back online. You should not, however, need to rebuild the documentation (mgrep.pdf) because it is included along with the shell-script (mgrep) and gawk file (mgrep.awk). To use the tool you will need to install mgrep and mgrep.awk in a directory in your path. The --help option prints a brief help page.
Here I use mgrep to partially explore a question that acer poses, that, whether % may be usefully employed in a Maple procedure. A reasonable start is to see whether it is so used in the distributed Maple library. First I go to the lib subdirectory of the Maple installation, then call mgrep to search maple.mla for all procedures that use % as a name