Which 'sed' command is used to replace the first occurrence of a pattern in each line?*1 pointa) s/old/newb) g/old/newc) /old/newd) r/old/new

Break Down the Problem

1. Identify the purpose of the 'sed' command.
2. Analyze the provided options for replacing patterns.

Relevant Concepts

• The 'sed' command, short for Stream Editor, is used for parsing and transforming text in Unix-like operating systems.
• The syntax for substitution in 'sed' is s/pattern/replacement/, where the s stands for substitute.

Analysis and Detail

1. Option a: s/old/new - This command replaces the first occurrence of "old" with "new" on each line.
2. Option b: g/old/new - The g option signifies a global replacement, which replaces all occurrences, not just the first.
3. Option c: /old/new - This syntax does not conform to the proper 'sed' substitution command structure.
4. Option d: r/old/new - The r command is used for reading from a file, not for replacement.

Verify and Summarize

Upon evaluating the options, the only command that clearly states it replaces the first occurrence of a pattern in each line is option a.

Final Answer

The correct answer is a) s/old/new.