[Solved] Why does ${#var} return 0 when var is unset in bash? - Ans: Because an unset variable is treated as an empty string | Bash Scripting

Bash Scripting - String Operations

Why does ${#var} return 0 when var is unset in bash?

ABecause an unset variable is treated as an empty string

BBecause bash throws an error for unset variables

CBecause ${#var} counts words, not characters

DBecause variable length is undefined if unset

Step-by-Step Solution

Solution:

Step 1: Understand unset variable behavior
In bash, an unset variable is treated as an empty string when expanded.
Step 2: ${#var} returns length of empty string as 0
Therefore, length is zero, no error occurs.
Final Answer:
Because an unset variable is treated as an empty string -> Option A
Quick Check:
Unset var length = 0 [OK]

Quick Trick: Unset variables act like empty strings for length [OK]

Common Mistakes:

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Why does ${#var} return 0 when var is unset in bash?