Sed- 10 Practical Uses of Sed

sed

This command is used in order to searches through, replaces, adds, and deletes lines in a text file.

10 Practical Uses of Sed

• Replace a specific word in a text file.

 sed 's/oldword/newword/g' file.txt

The s command stands for Replace and g stands for global. This command will replace all the oldword with newword in file.txt.

• Remove blank lines from a file.

 sed '/^$/d' file.txt

^$ will match the blank lines and d represents delete the line it will delete all the blank lines in file.txt.

• Replace characters in specific line numbers.

 sed '2s/oldchar/newchar/g' file.txt

'2' represents line number and on this line, command will replace all oldchar with newchar in file.txt.

• Delete specific character in a file.

 sed 's/char//g' file.txt

char specify character to delete and //g will delete all the specified characters in file.txt.

• Replace multiple characters in a file

sed 's/[char1char2]//g' file.txt

Inside square brackets specify all the characters that need to be deleted in file.txt.

• Delete the last line of a file.

sed '$d' file.txt

$d delete the last line of a file.txt, where $ matches the last line.

• Delete a range of lines in a file.

sed '10,20d' file.txt

This command deletes all the lines from 10 - 20 both lines included.

• Print first 10 lines of file.

sed -n '1,10p' file.txt

The -n option suppresses automatic output, and 1,10p print lines from 1 to 10 inclusive.

• Delete a range of lines in file.

sed '10,20d' file.txt

The 10,20d command deletes lines 10 to 20 inclusive in the file.

• Insert a line before the first line of a file.

sed '1i\new-line' file.txt

1i insert the text "new-line" before the first line of the file.