Get `grep` to not output file name When I use `grep -o` to search in multiple files, it outputs each result prefixed with the file name. How can I prevent this prefix? I want the results without the file names.

With the GNU implementation of `grep` (the one that also introduced `-o`) or compatible, you can use the `-h` option.

>
> -h, --no-filename
> Suppress the prefixing of file names on output. This is the
> default when there is only one file (or only standard input) to
> search.
>

With other implementations, you can always concatenate the files with `cat` and `grep` that output:


cat ./*.txt | grep regexp


Or use `sed` or `awk` instead of `grep`:


awk '/regexp/' ./*.txt


(extended regexps like with `grep -E`).


sed '/regexp/!d/' ./*.txt


(basic regexps like with `grep` without `-E`. Many `sed` implementations now also support a `-E` option for extended regexps).