2023年12月6日 — In bash scripting, the -z option checks if a string is null or empty. It can be used in an if statement, with the syntax if [ -z $variable ] .
2014年1月16日 — -w file Checks if file is writable; if yes, then the condition becomes true. [ -w $file ] is true. -x file Checks if file is executable; if yes, ...
2018年5月25日 — The -z flag causes test to check whether a string is empty. Returns true if the string is empty, false if it contains something. NOTE: The -z ...