[Solved] What does the sed command sed 's/hello/world/' file.txt do? — Ans: Replaces the first occurrence of 'hello' with 'world' in each line of file.txt | Linux CLI

Linux CLI - Text Processing

What does the sed command sed 's/hello/world/' file.txt do?

ADeletes all lines containing 'hello' from file.txt

BAppends 'world' to the end of each line in file.txt

CPrints only lines containing 'hello' from file.txt

DReplaces the first occurrence of 'hello' with 'world' in each line of file.txt

Step-by-Step Solution

Solution:

Step 1: Understand the sed substitution syntax
The command uses 's/old/new/' which means substitute the first occurrence of 'old' with 'new' in each line.
Step 2: Apply to the given command
Here, 'hello' is replaced by 'world' once per line in file.txt.
Final Answer:
Replaces the first occurrence of 'hello' with 'world' in each line of file.txt -> Option D
Quick Check:
sed substitution = Replaces first occurrence [OK]

Quick Trick: sed 's/old/new/' replaces first match per line [OK]

Common Mistakes:

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