[Solved] Which bash snippet correctly checks if the variable input is empty by using string length? - Ans: if [ ${#input} -eq 0 ]; then echo "Empty"; fi | Bash Scripting

Bash Scripting - String Operations

Which bash snippet correctly checks if the variable input is empty by using string length?

Aif [ $input -eq 0 ]; then echo "Empty"; fi

Bif [ ${#input} -eq 0 ]; then echo "Empty"; fi

Cif [ -z ${input} ]; then echo "Empty"; fi

Dif [ ${input} == "" ]; then echo "Empty"; fi

Step-by-Step Solution

Solution:

Step 1: Understand string length check
Using ${#input} gives the length of the string.
Step 2: Check for zero length
Comparing ${#input} to 0 correctly tests if the string is empty.
Step 3: Analyze other options
if [ $input -eq 0 ]; then echo "Empty"; fi tries numeric comparison on string content, invalid. if [ -z ${input} ]; then echo "Empty"; fi lacks quotes and may cause errors if input is unset. if [ ${input} == "" ]; then echo "Empty"; fi uses string comparison but is less reliable without quotes.
Final Answer:
if [ ${#input} -eq 0 ]; then echo "Empty"; fi -> Option B
Quick Check:
Test with input="" outputs "Empty" [OK]

Quick Trick: Check if ${#var} equals 0 to test empty string [OK]

Common Mistakes:

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Which bash snippet correctly checks if the variable input is empty by using string length?