simple awk and sed

awk and sed are two powerful command line tools for text processing. The only usage I will use are these two. For all the other complicated tasks I would prefer to use python.

awk '{print $1 " " $2 " " $3}' input > output

sed 's/wrong/right/' input > output

sed "/&word_after_which_to_insert/ r file_insert" template.inp > out.inp