我正在尝试使用该类，extarticle.cls但是当我编译时收到一条错误消息，提示无法找到该类。
! LaTeX Error: File 'extarticle.cls' not found.
由于我使用的是 Debian 系统，所以我检查了该类附带的软件包，发现它已捆绑在软件包中texlive-latex-recommended。我确认已安装。
apt list texlive* --installed
Listing... Done
texlive-base/groovy,groovy,now 2020.20200804-2 all [installed,automatic]
texlive-bibtex-extra/groovy,groovy,now 2020.20200804-3 all [installed]
texlive-binaries/groovy,now 2020.20200327.54578-4build1 amd64 [installed,automatic]
texlive-extra-utils/groovy,groovy,now 2020.20200804-3 all [installed]
texlive-fonts-recommended/groovy,groovy,now 2020.20200804-2 all [installed,automatic]
texlive-latex-base/groovy,groovy,now 2020.20200804-2 all [installed,automatic]
texlive-latex-recommended/groovy,groovy,now 2020.20200804-2 all [installed]
texlive-luatex/groovy,groovy,now 2020.20200804-2 all [installed,automatic]
texlive-plain-generic/groovy,groovy,now 2020.20200804-3 all [installed,automatic]
texlive/groovy,groovy,now 2020.20200804-2 all [installed]
然后我查看了这些文件并确认这些文件具有读取权限。
ls -l /usr/share/texlive/texmf-dist/tex/latex/extsizes/
total 140
-rw-r--r-- 1 root root 2201 Jan 12 2006 autopagewidth.sty
-rw-r--r-- 1 root root 20602 Jan 12 2006 extarticle.cls
-rw-r--r-- 1 root root 23153 Jan 12 2006 extbook.cls
-rw-r--r-- 1 root root 14088 Jan 12 2006 extletter.cls
-rw-r--r-- 1 root root 2573 Jan 12 2006 extproc.cls
-rw-r--r-- 1 root root 23786 Jan 12 2006 extreport.cls
-rw-r--r-- 1 root root 3240 Jan 12 2006 extsizes.sty
-rw-r--r-- 1 root root 6214 Jan 12 2006 size14.clo
-rw-r--r-- 1 root root 6192 Jul 16 2007 size17.clo
-rw-r--r-- 1 root root 6196 Jul 16 2007 size20.clo
-rw-r--r-- 1 root root 6172 Jan 12 2006 size8.clo
-rw-r--r-- 1 root root 6172 Jan 12 2006 size9.clo
我猜想 texlive 查找文件的 PATH 有问题，但我不知道怎么回事。我应该怎么做才能让 texlive 指向正确的方向？
Texlive 版本：
pdfTeX 3.14159265-2.6-1.40.21 (TeX Live 2020)
kpathsea version 6.3.2
Copyright 2020 Han The Thanh (pdfTeX) et al.
There is NO warranty. Redistribution of this software is
covered by the terms of both the pdfTeX copyright and
the Lesser GNU General Public License.
For more information about these matters, see the file
named COPYING and the pdfTeX source.
Primary author of pdfTeX: Han The Thanh (pdfTeX) et al.
Compiled with libpng 1.6.37; using libpng 1.6.37
Compiled with zlib 1.2.11; using zlib 1.2.11
Compiled with xpdf version 4.02
操作系统：
NAME="Pop!_OS"
VERSION="20.10"
ID=pop
ID_LIKE="ubuntu debian"
日志档案：
This is pdfTeX, Version 3.14159265-2.6-1.40.21 (TeX Live 2020) (preloaded format=pdflatex 2021.3.6) 9 JUN 2021 17:53 entering extended mode
restricted \write18 enabled.
%&-line parsing enabled.
**template.tex
(./template.tex
LaTeX2e <2020-10-01> patch level 4
L3 programming layer <2021-02-18>
! LaTeX Error: File `extarticle.cls' not found.