replace string

sed -e 's/\/.*\///g'
  • remove /.*/ (directory structure from file)

join ldif lines together

sed -e :a -e '$!N;s/\n //;ta' -e 'P;D' file
  • Append lines that start with a space to the previous line

insert a line after a specific line number

sed -i "3i hello" t.txt
  • Insert a line at the 3rd line of the file t.txt that says “hello”
  • -i is to replace the existing file rather than creating new.
sed -i "6i exit 0;" 
  • insert “exit 0;” after the 6th line of the file

delete a specific line

sed -e '/uniquemember: cn=null/Id' test.ldif
  • delete lines that match string
  • I = case insensitive

convert to lowercase

sed -e 's/\(.*\)/\L\1/'