Question

I want to find all the lines in my text file containing the string "abc", but not containing the string "def". Can I use the grep command to accomplish this task?

Answer 1

Either of the these will do:

grep -v "def" input_file | grep "abc"

or

grep "abc" input_file | grep -v "def"

The following will also preserve coloring if you only want to see the output on stdout:

grep --color=always "abc" input_file | grep -v "def"

The -v option (stands for “invert match”) tells grep to ignore the lines with the specified pattern – in this case def.