File & String Tests in Bash
From the Bash Scripting cheat sheet · Conditionals · verified Jul 2026
File & String Tests
Common test operators.
bash
# Quick Reference
[[ -f file ]] # regular file exists
[[ -d dir ]] # directory exists
[[ -z "$s" ]] # string is empty
[[ "$a" == "$b" ]] # strings equal💡 -f tests a regular file; -e tests any path; -d tests a directory.
⚡ Always quote the value in string tests ([[ -z "$s" ]]) to handle empties safely.
📌 Use -eq/-lt/-gt for numbers and ==/</> for strings - mixing them miscompares.
🟢 (( n > 5 )) reads more naturally than [[ "$n" -gt 5 ]] for pure number checks.
testsfiles
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