Interview › Scripting (Bash, Groovy)
What is command substitution, and what is the difference between $(...) and backticks? [Basic]
Answer
Command substitution runs a command and replaces the expression with its stdout. $(...) is preferred over backticks because it is easier to read, nest, and quote correctly.
Technical explanation
Command substitution strips trailing newlines from the captured output.
Always quote the substitution unless you deliberately want splitting: value=$(cmd); echo "$value".
Backticks require awkward escaping when nested; $(...) nests naturally.
Hands-on example
today=$(date +%F)commit=$(git rev-parse --short HEAD)image="registry.example.com/api:${today}-${commit}"echo "$image"
nested=$(basename "$(pwd)")echo "current directory name: $nested
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