関連ワード:  check if env variable is defined bash    check if environment variable is defined bash    check if env variable is set bash    check if environment variable is set bash    check if environment variable is set shell    check if env variable exists bash    check if environment variable is not set bash    check if env var exists bash    bash check if env variable is set to true    check if environment variable exists shell  
結果 : check if env variable is defined bash