I need something that can quickly search through many .txt, .pdf, and .doc files (.djvu also preferable). Can anyone here name or recommend such a tool (Windows platform) ?
PowerGREP is another suggestion.
From their website:
PowerGREP is a powerful Windows grep tool. Quickly search through large numbers of files on your PC or network, including text and binary files, compressed archives, MS Word documents, Excel spreadsheets, PDF files, OpenOffice files, etc. Find the information you want with powerful text patterns (regular expressions) specifying the form of what you want, instead of literal text.
It's not free, (it costs $149) but it appears to be the best fit for what you're looking for (except the DJVU one - I haven't found anything that can search through them yet.)
I use WinGrep for this purpose. Free, small, works really good.
I used the Copernic Desktop Search for a while. It even manages to search through email attachments.
I use AstroGrep:
AstroGrep is a Microsoft Windows grep utility. Grep is a UNIX command-line program which searches within files for keywords. AstroGrep supports regular expressions, versatile printing options, stores most recently used paths and has a "context" feature which is very nice for looking at source code.
.. and the best: it's free.
I'd suggest you look at File Content Finder (disclaimer - I'm its developer). It's specifically designed for searching file contents without indexing. It supports all major file formats - pdf, doc(x), xls(x), pptx, rtf, and others.
Its filtering lets you optimise and refine your search by multiple criteria - file type, creation/modification dates, etc.
Agent Ransack is a similar app, but only works on Windows and supports fewer file formats (doesn't support doc files!).
I have your answer!!! You need to install cygwin for windows. This will let you use *Unix commands in a windows environment and it is totally free. Once you get it installed you can use the regular 'grep' function to search anything you want.
Here is the download link: http://www.cygwin.com/setup.exe
Windows Search 4.0 for Windows XP (KB940157) will bring the Vista/7 searching experience to XP. ;-)