Hi there! .
I am a bit of a newbie (using Mint 18), but I have come across these issue of searching files by content and I had to thoroughly research that. Here is what I came up with, after posting questions on this forum and others:
Popular search options are no good for content search:
Searchmonkey - only searching by file name
FSearch - only searching by file name
Nemo has a good search by file name, but NOT content
Catfish - can search contents BUT only for plain text files, NOT for .odf or .doc
TO SEARCH TEXT FILES BY CONTENT REGARDLESS OF FILE TYPE: only two options exist: Docfetcher and Recoll (OR you can learn to do it in the command line)
Docfetcher - a little harder to install (need to install Java runtime); easier interface for newbie
Recoll - install in software centre, but must install helpers as well; more advanced interface
Recoll is for pros, if you are one - go for it, BUT you need to install "helpers" to search particular file types (see their documentation)
Docfetcher is my choice, absolutely love it.
Installation is a bit tedious, must install Runtime Java, then install from a .zip archive. It does not add itself to applications menu, you have to launch it from a .sh file (the "GTK2" file in the archive is what I used in Ubuntu 18 VM), and the help menu is hidden in the folder in the archive. But, once you sort it all out -
you don't have to worry about installing any "helpers" as with Recoll, it searches ALL formats
website:
http://docfetcher.sourceforge.net/en/download.html
how to install java:
https://www.pcsteps.com/5492-how-to-...x-mint-ubuntu/
Recoll (from software manager) - not newbie friendly, but can search contents of other formats
need to "index" (via menu) every time files change; by default searches only home directory, but can change in menu
once search the directory with particular format files, then look at "missing helpers" in the menu
to search odf, pdf and doc files:
sudo apt-get install python-libxslt1
sudo apt-get install antiword
to check if installed already: java -version
COMMMAND LINE - as an example, here is the way of searching many .odt files: (
https://www.linuxquestions.org/quest...39#post5916739)