AWK

    seq 5 | awk '{sum+=$1} END {print sum}'

useful for splitting columns 

ls -lh | awk '{ print $2 }'

just outputs the 2nd column (which is the package name)

    dpkg --list | grep linux-image | awk '{ print $2 }'

SED

basic edit

sed -i 's/ugly/beautiful/g' /home/usr/test.txt

batch edit

#!/bin/bash
for filename in *.php; do
    # backup old file
    mv $filename $filename.bck
    # edit file
    sed 's/FINDSTRING/REPLACESTRING/g' $filename.bck > $filename
 
    echo $filename.bck
    #rm -f $filename.bck
done

find eand edit: 

find /home/usr/test -type f -exec sed -i 's/ugly/beautiful/g' {} \;

add line at beginning of text file: 

sed -i '1s/^/text text\n/' file.txt