Environment:
    LANG                When target_lang is "auto", will use LANG as target_lang. If LANG is empty, will use zh_CN.
    XDG_CONFIG_HOME     See https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html
    XDG_DATA_HOME       Same as above.
    XDG_DATA_DIR        Same as above.
    HOME                User's home directory.
    SHELL               User's shell.

Files:
    .../config.py       Config file can be seen by:

                        trans --print-setting config_file
    .../history.txt     History file can be seen by:

                        trans --print-setting history_file
    .../stardict/dic/   stardict dictionary directory
                        like STARDICT_DATA_DIR of sdcv(1) can be seen by:

                        trans --print-setting stardict_dirs

Examples:
    clipper | trans     Translate clipboard. Clipper can be seen by

                        trans --print-setting clipper
    trans Free as in Freedom
                        Translate by CLI.
    trans               Translate by REPL.

Report bugs to https://github.com/Freed-Wu/translate-shell/issues .
