Address and address range

Introduction#

Sed commands can be specified to act only on certain lines by using addresses or address ranges.

Specific line

$ cat ip.txt
address
range
substitution
pattern
sample

• Nth line

  $ sed -n '2p' ip.txt 
  range
  
  $ sed '3d' ip.txt 
  address
  range
  pattern
  sample

• Last line

  $ sed -n '$p' ip.txt 
  sample

Specific range of lines

$ cat ip.txt 
address
range
substitution
pattern
sample

• Range specified is inclusive of those line numbers

  $ sed -n '2,4p' ip.txt 
  range
  substitution
  pattern

• $ can be used to specify last line. Space can be used between address and command for clarity

  $ sed -n '3,$ s/[aeiou]//gp' ip.txt 
  sbstttn
  pttrn
  smpl

• ith line to i+jth line

  $ sed '2,+2d' ip.txt 
  address
  sample

• ith line and i+j, i+2j, i+3j, etc.

  $ sed -n '1~2p' ip.txt 
  address
  substitution
  sample

Lines matching regular expression pattern

$ cat ip.txt 
address
range
substitution
pattern
sample
Add Sub Mul Div

• Lines matching a pattern

  $ sed '/add/d' ip.txt 
  range
  substitution
  pattern
  sample
  Add Sub Mul Div
  
  $ sed -n '/t/p' ip.txt 
  substitution
  pattern
  
  $ sed -n '/[A-Z]/ s| |/|gp' ip.txt 
  Add/Sub/Mul/Div

• Range of patterns

  $ sed -n '/add/,/sub/p' ip.txt 
  address
  range
  substitution
  
  $ sed -n '/a/,/e/p' ip.txt 
  address
  range
  pattern
  sample

Note

• In the second example, it matched two ranges - lines 1,2 and lines 4,5
• See Using different delimiters on how to use other characters instead of / for specifying the pattern

• Case-insensitive match

  $ sed -n '/add/Ip' ip.txt 
  address
  Add Sub Mul Div
  
  $ sed -n '/add/I,/sub/p' ip.txt 
  address
  range
  substitution
  Add Sub Mul Div

Specifying range using both number and pattern

$ cat ip.txt 
address
range
substitution
pattern
sample
Add Sub Mul Div

• Line number to line matching pattern

  $ sed -n '2,/pat/p' ip.txt 
  range
  substitution
  pattern

• Line matching pattern to line number

  $ sed '/pat/,$d' ip.txt 
  address
  range
  substitution

• Line matching pattern plus number of lines following it

  $ sed -n '/add/I,+1p' ip.txt 
  address
  range
  Add Sub Mul Div

• 0 can be used as starting line number to signal end of range when pattern matches first line of input

  $ sed -n '0,/r/p' ip.txt 
  address
  
  $ sed -n '1,/r/p' ip.txt 
  address
  range
  
  $ sed -n '0,/u/p' ip.txt 
  address
  range
  substitution

Negating address range

$ cat ip.txt 
address
range
substitution
1234
search pattern
sample
Add Sub Mul Div

• Deleting lines other than address specified

  $ sed '/[0-9]/!d' ip.txt 
  1234
   
  $ sed -n '/[0-9]/p' ip.txt 
  1234
    
  $ sed '$!d' ip.txt 
  Add Sub Mul Div
    
  $ sed -n '$p' ip.txt 
  Add Sub Mul Div

• Search and replace on lines not matching a pattern

  $ sed '/ /! s/^/#/' ip.txt 
  #address
  #range
  #substitution
  #1234
  search pattern
  #sample
  Add Sub Mul Div
  
  $ sed '/add/,/sub/! s/[aeiou]//gi' ip.txt 
  address
  range
  substitution
  1234
  srch pttrn
  smpl
  dd Sb Ml Dv