# Add a comment to line with matching pattern
sed -e '/matchme/ s!^!#!' /etc/people

# Change a login shell in passwd for user
sed -e '/^pfowler:/ s!:/bin/false$!:/bin/bash!'

# Replace new lines with a character (;)
sed ':a;N;$!ba;s/\n/;/g'

# Replace commas with a new line
tr , '\n'

# Ignore first line
awk '{if (NR != 1) {print $1}}'
 
# Change Input & Output separators
awk -F":" -v OFS=',' '{print $1, $2, 9}' <filename>
 
# Sum a column
du -ks /home/*/www | awk '{ SUM += $1} END { print SUM/1024 }'
 
# Print last column
awk '{print $NF}'

Print 1st few cols, then from col 9 → end. Example below works for ls -la

#!/bin/bash
# Provide a text file in first argument
 
awk -F\  ' {
printf("%s,%s,%s,%s-%s-%s,", $3, $4, $5, $8, $7, $6) 
for (i=9; i<=NF; i++)
        printf("%s ", $i)
printf("\n") 
} ' $1