Fun working with files using awk and sed

There are two awesome Linux commands providing a great flexibility in manipulating with text files: awk and sed. These commands sadly are not so popular and widely highlighted as another Linux commands. Let’s see what we can do with these commands.

awk

Print all line containing string

awk '/mtllib/' test.txt

Print line number for lines containing substring

awk '/mtllib/ {print NR, $1, $2}' test.txt

Print fifth line

awk 'NR==5 {print}' test.txt

Print number of lines in file

awk 'END {print NR}'

Interesting trick: compare output of two commands awk using command diff

awk '{print $3}' f1.txt | sort -u > out1
awk '{print $2}' f2.txt | sort -u > out2
diff out1 out2

sed

Print lines in range numbers in file

sed -n '3,6 p' test.txt

Replace substring in file:

sed -i 's|Old|New|' test.txt

Replace substring by regex (all occurrences of ‘2/<digit>’ replace with ‘2’)

sed -i 's|2/.|2|g' test.txt

Delete lines containing specific pattern

sed -i '/debian/d' file

Add text to the beginning of file

sed -i '1isome text' test.txt

Here we add text ‘some text’ in the first line of file test.txt.

That’s it. Enjoy work with files using awk and sed commands.