This is the second note on Text Manipulations with Linux Sed. The first note coverts Append and Insert to a file using sed. It also covers the Option Switches. And, the third note will covers Print Lines using sed.
To test each of the commands and options, let’s use the following files as an example:
#> cat sed_edit.txt
New York, Big Apple
Washington DC, The Capital
New Jersey, Garden Stata
Paris, The City of Light
Hong Kong, Pearl of the Orient
1. Use Sed ‘c\’ to replace a line indicate by the address
Following is the Syntax to replace a line with address:
#sed 'ADDRESS a\
Line which you want to replace' filename
‘ADDRESS’ is a number with represents the line, i.e.,3, represent the 3rd line.
Here am examples using sed replace with address command:
• Replace 3rd line with ,” San Francisco, Golden City”
#> sed '3 c\San Francisco, Golden City' sed_edit.txt
New York, Big Apple
Washington DC, The Capital
San Francisco, Golden City
Paris, The City of Light
Hong Kong, Pearl of the Orient
2 Use Sed ‘c\’ to replace a line that match with a pathern
Following is the Syntax to append a line with a match of a pattern:
#sed '/PATTERN/ c\
Line which you want to replace' filename
Here is an example using sed replace to replace a line of match of pattern to a file.
• There is a typo in line “New Jersey, Garden Stata” with the word “Stata”. Let’s replace it.
#>sed '/New Jersey, Garden Stata/ c\New Jersey, Garden State' sed_edit.txt
New York, Big Apple
Washington DC, The Capital
New Jersey, Garden State
Paris, The City of Light
Hong Kong, Pearl of the Orient
2.Sed Delete
2.1 Use Sed ‘d’ to delete line(s) indicate by the address
Following is the Syntax to replace a line with address:
#>sed ‘ADDRESS d’ inputfilename
Please note there is no “backslash”(“\”) after d.
There are some examples use sed delete command to delete line(s) from a input file.
• Example 1: delete the 3rd line from the file.
# sed ‘3d’ sed_edit.txt
New York, Big Apple
Washington DC, The Capital
Paris, The City of Light
Hong Kong, Pearl of the Orient
• Example 2: delete the line 2 to line 4 from the file.
# sed '2,4d' sed_edit.txt
New York, Big Apple
Hong Kong, Pearl of the Orient
2.2 Use Sed ‘d’ to delete line(s) indicate by match of pattern
Following is the Syntax to replace a line with address:
#sed ‘/PATTERN/ d’ inputfilename
Here some examples use sed delete command with match of pattern to delete line(s) from a input file.
• Example 1: delete line matches a given pattern.
Delete the line “New Jersey, Garden Stata” from the file
#>sed '/New Jersey, Garden Stata/ d' sed_edit.txt
New York, Big Apple
Washington DC, The Capital
Paris, The City of Light
Hong Kong, Pearl of the Orient
• Example 2: delete all the blank link from a file
Let’s change the file to look like this:
#>cat sed_edit.txt
New York, Big Apple
Washington DC, The Capital
New Jersey, Garden Stata
Paris, The City of Light
Hong Kong, Pearl of the Orient
Now, use delete to remove all blank lines.
#>sed '/^$/d' sed_edit.txt
New York, Big Apple
Washington DC, The Capital
New Jersey, Garden Stata
Paris, The City of Light
Hong Kong, Pearl of the Orient
• Example 3: delete multiple lines starting from the the line that matches a given pattern
Delete the lines that match “Paris” and all lines that after this lines
#>sed '/Paris/,$d' sed_edit.txt
New York, Big Apple
Washington DC, The Capital
New Jersey, Garden Stata
• Example 4: delete 1 addition lines from the match pattern
Delete the line that matches “Paris” and one more line after that
#sed '/Paris/,+1d' sed_edit.txt
New York, Big Apple
Washington DC, The Capital
New Jersey, Garden Stata
References:
- sed & awk
- Append and Insert, And Write To A File Using Sed
- Print Lines Using Sed
- Other reference on the web
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