我正在尝试使用 R Studio、R 版本 3.6.3 和 MacTex（TeX Live）从 *.Rmd 文件创建 pdf。
在（成功？）对 R 本身中的另一个错误消息进行故障排除后，立即出现了此错误：https://community.rstudio.com/t/using-rmarkdown-with-tex-live-2019-the-directory-usr-local-texlive-2019-tlpkg-is-not-writable/60310
为了解决之前的问题，我安装kvoptions了sudo tlmgr --verify-repo=none install kvoptions。
我的代码：
---
title: "Test"
output: pdf_document
---
```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```
错误信息：
processing file: Untitled.Rmd
/usr/local/bin/pandoc +RTS -K512m -RTS Untitled.utf8.md --to latex --from markdown+autolink_bare_uris+tex_math_single_backslash --output Untitled.tex --self-contained --highlight-style tango --pdf-engine pdflatex --variable graphics --lua-filter /Users/Jo/Library/R/3.6/library/rmarkdown/rmd/lua/pagebreak.lua --lua-filter /Users/Jo/Library/R/3.6/library/rmarkdown/rmd/lua/latex-div.lua --variable 'geometry:margin=1in'
output file: Untitled.knit.md
! Undefined control sequence.
l.10 \ifnum 0\ifxetex
1\fi\ifluatex 1\fi=0 % if pdftex
Error: LaTeX failed to compile Untitled.tex. See https://yihui.org/tinytex/r/#debugging for debugging tips. See Untitled.log for more info.
This is pdfTeX, Version 3.14159265-2.6-1.40.20 (TeX Live 2019) (preloaded format=pdflatex 2020.4.8) 8 APR 2020 22:55
entering extended mode
restricted \write18 enabled.
%&-line parsing enabled.
**Untitled.tex
(./Untitled.tex
LaTeX2e <2018-12-01>
(/usr/local/texlive/2019/texmf-dist/tex/latex/base/article.cls
Document Class: article 2018/09/03 v1.4i Standard LaTeX document class
(/usr/local/texlive/2019/texmf-dist/tex/latex/base/size10.clo
File: size10.clo 2018/09/03 v1.4i Standard LaTeX file (size option)
)
\c@part=\count80
\c@section=\count81
\c@subsection=\count82
\c@subsubsection=\count83
\c@paragraph=\count84
\c@subparagraph=\count85
\c@figure=\count86
\c@table=\count87
\abovecaptionskip=\skip41
\belowcaptionskip=\skip42
\bibindent=\dimen102
) (/usr/local/texlive/2019/texmf-dist/tex/latex/lm/lmodern.sty
Package: lmodern 2009/10/30 v1.6 Latin Modern Fonts
LaTeX Font Info: Overwriting symbol font `operators' in version `normal'
(Font) OT1/cmr/m/n --> OT1/lmr/m/n on input line 22.
LaTeX Font Info: Overwriting symbol font `letters' in version `normal'
(Font) OML/cmm/m/it --> OML/lmm/m/it on input line 23.
LaTeX Font Info: Overwriting symbol font `symbols' in version `normal'
(Font) OMS/cmsy/m/n --> OMS/lmsy/m/n on input line 24.
LaTeX Font Info: Overwriting symbol font `largesymbols' in version `normal'
(Font) OMX/cmex/m/n --> OMX/lmex/m/n on input line 25.
LaTeX Font Info: Overwriting symbol font `operators' in version `bold'
(Font) OT1/cmr/bx/n --> OT1/lmr/bx/n on input line 26.
LaTeX Font Info: Overwriting symbol font `letters' in version `bold'
(Font) OML/cmm/b/it --> OML/lmm/b/it on input line 27.
LaTeX Font Info: Overwriting symbol font `symbols' in version `bold'
(Font) OMS/cmsy/b/n --> OMS/lmsy/b/n on input line 28.
LaTeX Font Info: Overwriting symbol font `largesymbols' in version `bold'
(Font) OMX/cmex/m/n --> OMX/lmex/m/n on input line 29.
LaTeX Font Info: Overwriting math alphabet `\mathbf' in version `normal'
(Font) OT1/cmr/bx/n --> OT1/lmr/bx/n on input line 31.
LaTeX Font Info: Overwriting math alphabet `\mathsf' in version `normal'
(Font) OT1/cmss/m/n --> OT1/lmss/m/n on input line 32.
LaTeX Font Info: Overwriting math alphabet `\mathit' in version `normal'
(Font) OT1/cmr/m/it --> OT1/lmr/m/it on input line 33.
LaTeX Font Info: Overwriting math alphabet `\mathtt' in version `normal'
(Font) OT1/cmtt/m/n --> OT1/lmtt/m/n on input line 34.
LaTeX Font Info: Overwriting math alphabet `\mathbf' in version `bold'
(Font) OT1/cmr/bx/n --> OT1/lmr/bx/n on input line 35.
LaTeX Font Info: Overwriting math alphabet `\mathsf' in version `bold'
(Font) OT1/cmss/bx/n --> OT1/lmss/bx/n on input line 36.
LaTeX Font Info: Overwriting math alphabet `\mathit' in version `bold'
(Font) OT1/cmr/bx/it --> OT1/lmr/bx/it on input line 37.
LaTeX Font Info: Overwriting math alphabet `\mathtt' in version `bold'
(Font) OT1/cmtt/m/n --> OT1/lmtt/m/n on input line 38.
) (/usr/local/texlive/2019/texmf-dist/tex/latex/amsfonts/amssymb.sty
Package: amssymb 2013/01/14 v3.01 AMS font symbols
(/usr/local/texlive/2019/texmf-dist/tex/latex/amsfonts/amsfonts.sty
Package: amsfonts 2013/01/14 v3.01 Basic AMSFonts support
\@emptytoks=\toks14
\symAMSa=\mathgroup4
\symAMSb=\mathgroup5
LaTeX Font Info: Overwriting math alphabet `\mathfrak' in version `bold'
(Font) U/euf/m/n --> U/euf/b/n on input line 106.
)) (/usr/local/texlive/2019/texmf-dist/tex/latex/amsmath/amsmath.sty
Package: amsmath 2018/12/01 v2.17b AMS math features
\@mathmargin=\skip43
For additional information on amsmath, use the `?' option.
(/usr/local/texlive/2019/texmf-dist/tex/latex/amsmath/amstext.sty
Package: amstext 2000/06/29 v2.01 AMS text
(/usr/local/texlive/2019/texmf-dist/tex/latex/amsmath/amsgen.sty
File: amsgen.sty 1999/11/30 v2.0 generic functions
\@emptytoks=\toks15
\ex@=\dimen103
)) (/usr/local/texlive/2019/texmf-dist/tex/latex/amsmath/amsbsy.sty
Package: amsbsy 1999/11/29 v1.2d Bold Symbols
\pmbraise@=\dimen104
) (/usr/local/texlive/2019/texmf-dist/tex/latex/amsmath/amsopn.sty
Package: amsopn 2016/03/08 v2.02 operator names
)
\inf@bad=\count88
LaTeX Info: Redefining \frac on input line 223.
\uproot@=\count89
\leftroot@=\count90
LaTeX Info: Redefining \overline on input line 385.
\classnum@=\count91
\DOTSCASE@=\count92
LaTeX Info: Redefining \ldots on input line 482.
LaTeX Info: Redefining \dots on input line 485.
LaTeX Info: Redefining \cdots on input line 606.
\Mathstrutbox@=\box27
\strutbox@=\box28
\big@size=\dimen105
LaTeX Font Info: Redeclaring font encoding OML on input line 729.
LaTeX Font Info: Redeclaring font encoding OMS on input line 730.
\macc@depth=\count93
\c@MaxMatrixCols=\count94
\dotsspace@=\muskip10
\c@parentequation=\count95
\dspbrk@lvl=\count96
\tag@help=\toks16
\row@=\count97
\column@=\count98
\maxfields@=\count99
\andhelp@=\toks17
\eqnshift@=\dimen106
\alignsep@=\dimen107
\tagshift@=\dimen108
\tagwidth@=\dimen109
\totwidth@=\dimen110
\lineht@=\dimen111
\@envbody=\toks18
\multlinegap=\skip44
\multlinetaggap=\skip45
\mathdisplay@stack=\toks19
LaTeX Info: Redefining \[ on input line 2844.
LaTeX Info: Redefining \] on input line 2845.
) (/usr/local/texlive/2019/texmf-dist/tex/generic/iftex/ifxetex.sty
Package: ifxetex 2019/10/25 v0.7 ifxetex legacy package. Use iftex instead.
(/usr/local/texlive/2019/texmf-dist/tex/generic/iftex/iftex.sty
Package: iftex 2013/04/04 v0.2 Provides if(tex) conditional for PDFTeX, XeTeX,
and LuaTeX
)) (/usr/local/texlive/2019/texmf-dist/tex/generic/iftex/ifluatex.sty
Package: ifluatex 2019/10/25 v1.5 ifluatex legacy package. Use iftex instead.
)
! Undefined control sequence.
l.10 \ifnum 0\ifxetex
1\fi\ifluatex 1\fi=0 % if pdftex
Here is how much of TeX's memory you used:
1127 strings out of 492616
12976 string characters out of 6129482
72427 words of memory out of 5000000
5101 multiletter control sequences out of 15000+600000
3640 words of font info for 14 fonts, out of 8000000 for 9000
1141 hyphenation exceptions out of 8191
27i,0n,27p,233b,36s stack positions out of 5000i,500n,10000p,200000b,80000s
! ==> Fatal error occurred, no output PDF file produced!
无标题.tex：
% Options for packages loaded elsewhere
\PassOptionsToPackage{unicode}{hyperref}
\PassOptionsToPackage{hyphens}{url}
%
\documentclass[
]{article}
\usepackage{lmodern}
\usepackage{amssymb,amsmath}
\usepackage{ifxetex,ifluatex}
\ifnum 0\ifxetex 1\fi\ifluatex 1\fi=0 % if pdftex
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{textcomp} % provide euro and other symbols
\else % if luatex or xetex
\usepackage{unicode-math}
\defaultfontfeatures{Scale=MatchLowercase}
\defaultfontfeatures[\rmfamily]{Ligatures=TeX,Scale=1}
\fi
% Use upquote if available, for straight quotes in verbatim environments
\IfFileExists{upquote.sty}{\usepackage{upquote}}{}
\IfFileExists{microtype.sty}{% use microtype if available
\usepackage[]{microtype}
\UseMicrotypeSet[protrusion]{basicmath} % disable protrusion for tt fonts
}{}
\makeatletter
\@ifundefined{KOMAClassName}{% if non-KOMA class
\IfFileExists{parskip.sty}{%
\usepackage{parskip}
}{% else
\setlength{\parindent}{0pt}
\setlength{\parskip}{6pt plus 2pt minus 1pt}}
}{% if KOMA class
\KOMAoptions{parskip=half}}
\makeatother
\usepackage{xcolor}
\IfFileExists{xurl.sty}{\usepackage{xurl}}{} % add URL line breaks if available
\IfFileExists{bookmark.sty}{\usepackage{bookmark}}{\usepackage{hyperref}}
\hypersetup{
hidelinks,
pdfcreator={LaTeX via pandoc}}
\urlstyle{same} % disable monospaced font for URLs
\usepackage[margin=1in]{geometry}
\usepackage{graphicx}
\makeatletter
\def\maxwidth{\ifdim\Gin@nat@width>\linewidth\linewidth\else\Gin@nat@width\fi}
\def\maxheight{\ifdim\Gin@nat@height>\textheight\textheight\else\Gin@nat@height\fi}
\makeatother
% Scale images if necessary, so that they will not overflow the page
% margins by default, and it is still possible to overwrite the defaults
% using explicit options in \includegraphics[width, height, ...]{}
\setkeys{Gin}{width=\maxwidth,height=\maxheight,keepaspectratio}
% Set default figure placement to htbp
\makeatletter
\def\fps@figure{htbp}
\makeatother
\setlength{\emergencystretch}{3em} % prevent overfull lines
\providecommand{\tightlist}{%
\setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}
\setcounter{secnumdepth}{-\maxdimen} % remove section numbering
\author{}
\date{\vspace{-2.5em}}
\begin{document}
\end{document}
非常感谢！我对此很困惑