The here-document is great, but it’s messing up your shell script’s formatting. You want to be able to indent for readability.
Solution
Use <<- and then you can use tab characters (only!) at the beginning of lines to indent this portion of your shell script.
$ cat myscript.sh
...
grep $1 <<-'EOF'
lots of data
can go here
it's indented with tabs
to match the script's indenting
but the leading tabs are
discarded when read
EOF
Discussion
The hyphen just after the << is enough to tell bash to ignore the leading tab charac- ters. This is for tab characters only and not arbitrary white space. This is especially important with the EOF or any other marker designation. If you have spaces there, it will not recognize the EOF as your ending marker, and the “here” data will continue through to the end of the file (swallowing the rest of your script). Therefore, you may want to always left-justify the EOF (or other marker) just to be safe, and let the for- matting go on this one line.