awk one liners

# File Spacing

# double space a file
awk '1;{print ""}'
awk 'BEGIN{ORS="\n\n"};1'

# triple space
 awk '1;{print "\n"}'

 # precede each line by its line number FOR ALL FILES TOGETHER, with tab.
 awk '{print NR "\t" $0}' files*

 # count lines (emulates "wc -l")
 awk 'END{print NR}'

 # print every line after replacing each field with its absolute value
 awk '{for (i=1; i<=NF; i++) if ($i < 0) $i = -$i; print }'
 awk '{for (i=1; i<=NF; i++) $i = ($i < 0) ? -$i : $i; print }'

 # print the total number of lines that contain "Darn"
 awk '/Darn/{n++}; END {print n+0}' file

 # print the last field of the last line
 awk '{ field = $NF }; END{ print field }'

 # print every line with more than 4 fields
 awk 'NF > 4'

 # delete leading whitespace (spaces, tabs) from front of each line
 # aligns all text flush left
 awk '{sub(/^[ \t]+/, "")};1'

 # delete trailing whitespace (spaces, tabs) from end of each line
 awk '{sub(/[ \t]+$/, "")};1'

# grep for AAA and BBB and CCC (in any order on the same line)
 awk '/AAA/ && /BBB/ && /CCC/'

 # grep for AAA and BBB and CCC (in that order)
 awk '/AAA.*BBB.*CCC/'