sed

Question 1

sed

Answer 1

sed is a stream editor. A stream editor is used to perform basic text transformations on an input stream (a file or input from a pipeline).

Question 2

sed

• e
• f
• E, -r
• s

Answer 2

• e script, –expression=script, Add the script to the commands to be executed.
• f script-file, –file=script-file, Add the contents of script-file to the commands to be executed.
• E, -r, –regexp-extended, Use extended regular expressions in the script.
• s, –separate, Consider files as separate rather than as a single, continuous long stream.

Question 3

sed ‘ s/string1/string2/ ‘ file1.txt

Answer 3

This command substitutes and replaces the first occurance of string2 with string1.

Question 4

sed ‘ s/string1/string2/2 ‘ file1.txt

Answer 4

This command substitutes and replaces the second occurance of string2 with string1.

Question 5

sed ‘ s/string1/string2/g ‘ file1.txt

Answer 5

This command substitutes and replaces all occurences of string2 with string1. The /g stands for global.

Question 6

sed ‘ s/string1/string2/3g ‘ file1.txt

Answer 6

This command replaces string2 with string1 from the third occurance and beyond. Any number can be added to that range.