Here documents avoid creation of an intermediate, one-time use file. I was hoping to make use of this when getting the full paths of 20 possible files (without using find -o syntax). I expected the following to work:
find | grep -f <<EOF
Controller.java
Main.java
Config.java
EOF
but I get:
grep: option requires an argument -- f
Am I misunderstanding how here documents work? Or does grep -f not play nicely with file descriptors?
I'm also open to solutions with find that can take a list of -name values, but I don't want to have to type -o 20 times.
Best alternative:
cat <<EOF | xargs --delimiter '\n' --max-args=1 -I% find -iname "*%*"
Controller.java
Main.java
Config.java
EOF
This is intellectually unsatisfying because you're running find on the entire file hierarchy once for each search pattern which won't scale well for large directory hierarchies.
If you're on a system with /proc (eg linux), try:
#!/bin/sh
find . | grep -f /proc/self/fd/3 3<< EOF
Controller.java
Main.java
Config.java
EOF
Or, if your shell supports process substitution (Bourne Shell does not):
#!/bin/bash
find . | grep -f <( cat << EOF
Controller.java
Main.java
Config.java
EOF
)