How do I search the input text files for lines matching given words or strings under UNIX operating systems?
To search for a particular word or string in a file, use the grep command.
The basic syntax of the grep command is as follows:
grep string fileName grep word fileName grep "word1 word2" fileName
For example, to find Vivek Gite's email id, type grep, and the file containing the information:
grep Vivek users.txt grep "Vivek Gite" users.txt grep "Gite" users.txt
Vivek Gite 123-455-676 firstname.lastname@example.org
To search word apple in all text file (*.txt) enter:
grep apple *.txt
You can also search for lines without a certain words. For example, display all line that do not contain the word "usb"
grep -v "usb" *
See more grep command examples here.