perl: warning: Setting locale failed. 解決

perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
    LANGUAGE = (unset),
    LC_ALL = (unset),
    LC_TIME = "zh_CN.UTF-8",
    LC_MONETARY = "zh_CN.UTF-8",
    LC_ADDRESS = "zh_CN.UTF-8",
    LC_TELEPHONE = "zh_CN.UTF-8",
    LC_NAME = "zh_CN.UTF-8",
    LC_MEASUREMENT = "zh_CN.UTF-8",
    LC_IDENTIFICATION = "zh_CN.UTF-8",
    LC_NUMERIC = "zh_CN.UTF-8",
    LC_PAPER = "zh_CN.UTF-8",
    LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").

安裝軟件時，都會去執行 update-locale 命令，用來更新 locale。這個命令是 perl 腳本（可以用 whereis update-locale 查到）

上述警告並不是因為 update-locale 命令錯了，而是因為 perl 的配置出了問題。

可以使用以下命令只運行 perl 測試：

$ perl -e exit

perl 使用系統提供的默認 locale zh_CN.UTF-8，但這個值是 ssh 從客戶端傳遞來的，系統其實不知道 zh_CN.UTF-8 該如何處理。

我們安裝語言包即可解決問題：

$ apt-get install language-pack-zh-hans