I think you made a mistake in `english_words`

[emanuele6]

Maybe that's the behaviour you want, but I think you might have scripted this wrong.

#! /bin/sh

WORDS=$XDG_DATA_HOME/dicen.txt

[ -n "$@" ] && grep -E "$@" "$WORDS"

If you run this script with more than one argument, e.g. english_words hello hi, "$@" will get expanded to 'hello' 'hi' and grep will treat hello as the ERE and hi as the name of a file to search into before searching in "$WORDS".

---

If you want to search in "$WORDS" for hello hi (i.e. the arguments form a single ERE by getting joined with ) in that case, you can use "$*", instead of "$@", which will expand to 'hello hi', i.e.:

#! /bin/sh

WORDS="$XDG_DATA_HOME/dicen.txt"

[ -n "$*" ] && grep -E "$*" "$WORDS"

---

If you want to search in "$WORDS" for hello and for hi as if they were two distinct ERE, you can use this solution:

#! /bin/sh

WORDS="$XDG_DATA_HOME/dicen.txt"

for arg in "$@"; do
	grep -E "$arg" "$WORDS"
done

---

You could also just only use the first argument:

#! /bin/sh

WORDS="$XDG_DATA_HOME/dicen.txt"

[ -n "$1" ] && grep -E "$1" "$WORDS"