Question

What will be output of grep c tcs file.txt?

Answer 1

Grep command in Unix/Linux Grep  is a powerful tool that searches for matching a regular expression against text in a file, multiple files or a stream of input. It searches for the pattern of text that you specify on the command line and prints output for you.

In addition, three variant programs egrep,fgrep and rgrep are available.

egrep is the same as grep -E fgrep is the same as grep -Frgrep is the same as grep -r

Direct invocation as either egrep or fgrep is deprecated, but is provided to allow historical applications that rely on them to run unmodified.