man: can’t set the locale; make sure $LC_* and $LANG are correct
这个是语言设置的问题，通过 locale-gen 可以解决。
首先编辑文件 /etc/locale.gen， 最好添加 en_US.UTF-8 UTF-8 ，其的注释掉
locale-gen Generating locales (this might take a while)... en_US.UTF-8... done Generation complete.
LOCALE-GEN(8) System Manager's Manual LOCALE-GEN(8) NAME locale-gen — generates localisation files from templates SYNOPSIS locale-gen DESCRIPTION This manual page documents briefly the locale-gen command. By default, the locale package which provides the base support for lo‐ calisation of libc-based programs does not contain usable localisation files for every supported language. This limitation has became neces‐ sary because of the substantial size of such files and the large number of languages supported by libc. As a result, Debian uses a special mechanism where we prepare the actual localisation files on the target host and distribute only the templates for them. locale-gen is a program that reads the file /etc/locale.gen and invokes localedef for the chosen localisation profiles. Run locale-gen after you have modified the /etc/locale.gen file. FILES /etc/locale.gen The main configuration file, which has a simple format: every line that is not empty and does not begin with a # is treated as a locale defini‐ tion that is to be built. SEE ALSO localedef(1), locale(1), locale.gen(5). AUTHOR This manual page was written by Eduard Bloch <email@example.com> for the Debian GNU/Linux system (but may be used by others). Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts and no Back-Cover Texts. LOCALE-GEN(8) Manual page locale-gen(8) line 1/42 (END) (press h for help or q to quit)