\documentclass[10pt,a4paper]{article}

% Packages
\usepackage{fancyhdr}           % For header and footer
\usepackage{multicol}           % Allows multicols in tables
\usepackage{tabularx}           % Intelligent column widths
\usepackage{tabulary}           % Used in header and footer
\usepackage{hhline}             % Border under tables
\usepackage{graphicx}           % For images
\usepackage{xcolor}             % For hex colours
%\usepackage[utf8x]{inputenc}    % For unicode character support
\usepackage[T1]{fontenc}        % Without this we get weird character replacements
\usepackage{colortbl}           % For coloured tables
\usepackage{setspace}           % For line height
\usepackage{lastpage}           % Needed for total page number
\usepackage{seqsplit}           % Splits long words.
%\usepackage{opensans}          % Can't make this work so far. Shame. Would be lovely.
\usepackage[normalem]{ulem}     % For underlining links
% Most of the following are not required for the majority
% of cheat sheets but are needed for some symbol support.
\usepackage{amsmath}            % Symbols
\usepackage{MnSymbol}           % Symbols
\usepackage{wasysym}            % Symbols
%\usepackage[english,german,french,spanish,italian]{babel}              % Languages

% Document Info
\author{cizixs (cizixs)}
\pdfinfo{
  /Title (go-files.pdf)
  /Creator (Cheatography)
  /Author (cizixs (cizixs))
  /Subject (go files Cheat Sheet)
}

% Lengths and widths
\addtolength{\textwidth}{6cm}
\addtolength{\textheight}{-1cm}
\addtolength{\hoffset}{-3cm}
\addtolength{\voffset}{-2cm}
\setlength{\tabcolsep}{0.2cm} % Space between columns
\setlength{\headsep}{-12pt} % Reduce space between header and content
\setlength{\headheight}{85pt} % If less, LaTeX automatically increases it
\renewcommand{\footrulewidth}{0pt} % Remove footer line
\renewcommand{\headrulewidth}{0pt} % Remove header line
\renewcommand{\seqinsert}{\ifmmode\allowbreak\else\-\fi} % Hyphens in seqsplit
% This two commands together give roughly
% the right line height in the tables
\renewcommand{\arraystretch}{1.3}
\onehalfspacing

% Commands
\newcommand{\SetRowColor}[1]{\noalign{\gdef\RowColorName{#1}}\rowcolor{\RowColorName}} % Shortcut for row colour
\newcommand{\mymulticolumn}[3]{\multicolumn{#1}{>{\columncolor{\RowColorName}}#2}{#3}} % For coloured multi-cols
\newcolumntype{x}[1]{>{\raggedright}p{#1}} % New column types for ragged-right paragraph columns
\newcommand{\tn}{\tabularnewline} % Required as custom column type in use

% Font and Colours
\definecolor{HeadBackground}{HTML}{333333}
\definecolor{FootBackground}{HTML}{666666}
\definecolor{TextColor}{HTML}{333333}
\definecolor{DarkBackground}{HTML}{BA2337}
\definecolor{LightBackground}{HTML}{FAF1F2}
\renewcommand{\familydefault}{\sfdefault}
\color{TextColor}

% Header and Footer
\pagestyle{fancy}
\fancyhead{} % Set header to blank
\fancyfoot{} % Set footer to blank
\fancyhead[L]{
\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{C}
    \SetRowColor{DarkBackground}
    \vspace{-7pt}
    {\parbox{\dimexpr\textwidth-2\fboxsep\relax}{\noindent
        \hspace*{-6pt}\includegraphics[width=5.8cm]{/web/www.cheatography.com/public/images/cheatography_logo.pdf}}
    }
\end{tabulary}
\columnbreak
\begin{tabulary}{11cm}{L}
    \vspace{-2pt}\large{\bf{\textcolor{DarkBackground}{\textrm{go files Cheat Sheet}}}} \\
    \normalsize{by \textcolor{DarkBackground}{cizixs (cizixs)} via \textcolor{DarkBackground}{\uline{cheatography.com/43449/cs/12942/}}}
\end{tabulary}
\end{multicols}}

\fancyfoot[L]{ \footnotesize
\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{LL}
  \SetRowColor{FootBackground}
  \mymulticolumn{2}{p{5.377cm}}{\bf\textcolor{white}{Cheatographer}}  \\
  \vspace{-2pt}cizixs (cizixs) \\
  \uline{cheatography.com/cizixs} \\
        \uline{\seqsplit{cizixs}.com}
  \end{tabulary}
\vfill
\columnbreak
\begin{tabulary}{5.8cm}{L}
  \SetRowColor{FootBackground}
  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Cheat Sheet}}  \\
   \vspace{-2pt}Published 26th September, 2017.\\
   Updated 26th September, 2017.\\
   Page {\thepage} of \pageref{LastPage}.
\end{tabulary}
\vfill
\columnbreak
\begin{tabulary}{5.8cm}{L}
  \SetRowColor{FootBackground}
  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Sponsor}}  \\
  \SetRowColor{white}
  \vspace{-5pt}
  %\includegraphics[width=48px,height=48px]{dave.jpeg}
  Measure your website readability!\\
  www.readability-score.com
\end{tabulary}
\end{multicols}}




\begin{document}
\raggedright
\raggedcolumns

% Set font size to small. Switch to any value
% from this page to resize cheat sheet text:
% www.emerson.emory.edu/services/latex/latex_169.html
\footnotesize % Small font.

\begin{multicols*}{2}

\begin{tabularx}{8.4cm}{x{2.96 cm} x{5.04 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Basic Operations}}  \tn
% Row 0
\SetRowColor{LightBackground}
create empty file & `newFile, err := os.Create("test.txt")` \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
truncate a file & `err := os.Truncate("test.txt", 100)` \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
get file info & `fileInfo, err := os.State("test.txt")` \tn 
% Row Count 6 (+ 2)
% Row 3
\SetRowColor{white}
rename a file & `err := os.Rename(oldPath, newPath)` \tn 
% Row Count 8 (+ 2)
% Row 4
\SetRowColor{LightBackground}
delete a file & `err := os.Remove("test.txt")` \tn 
% Row Count 10 (+ 2)
% Row 5
\SetRowColor{white}
open a file for reading & `file, err := os.Open("test.txt")` \tn 
% Row Count 12 (+ 2)
% Row 6
\SetRowColor{LightBackground}
open a file & `file, err := os.Open("test.txt", os.O\_APPEND, 0600)` \tn 
% Row Count 15 (+ 3)
% Row 7
\SetRowColor{white}
close a file & `err := file.Close()` \tn 
% Row Count 16 (+ 1)
% Row 8
\SetRowColor{LightBackground}
change file permision & `err := os.Chmod("test.txt", 0777)` \tn 
% Row Count 18 (+ 2)
% Row 9
\SetRowColor{white}
change file ownership & `err := os.Chown("test.txt", os.Getuid(), os.Getgid())` \tn 
% Row Count 21 (+ 3)
% Row 10
\SetRowColor{LightBackground}
change file timestamps & `err := os.Chtimes("test.txt", lastAccessTime, lastModifyTime)` \tn 
% Row Count 24 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{2 cm} x{6 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{file open flag}}  \tn
% Row 0
\SetRowColor{LightBackground}
\seqsplit{`os.O\_RDONLY`} & open the file read only \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\seqsplit{`os.O\_WRONLY`} & open the file write only \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\seqsplit{`os.O\_RDWR`} & open the file read write \tn 
% Row Count 6 (+ 2)
% Row 3
\SetRowColor{white}
\seqsplit{`os.O\_APPEND`} & append data to the file when writing \tn 
% Row Count 8 (+ 2)
% Row 4
\SetRowColor{LightBackground}
\seqsplit{`os.O\_CREATE`} & create a new file if none exists \tn 
% Row Count 10 (+ 2)
% Row 5
\SetRowColor{white}
\seqsplit{`os.O\_EXCL`} & used with `O\_CREATE`, file must not exist \tn 
% Row Count 12 (+ 2)
% Row 6
\SetRowColor{LightBackground}
\seqsplit{`os.O\_SYNC`} & open for synchronous I/O \tn 
% Row Count 14 (+ 2)
% Row 7
\SetRowColor{white}
`O\_TRUNC` & if possible, truncate file when opened \tn 
% Row Count 16 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{8.4cm}}{When opening file with `os.OpenFile`, flags control how the file behaves.}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{2.8 cm} x{5.2 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Hard Link \& Symbol Link}}  \tn
% Row 0
\SetRowColor{LightBackground}
create a hard link & `err := os.Link("test.txt", "test\_copy.txt")` \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
create a symbol link & `err := os.Symlink("test.txt", "test\_sym.txt")` \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
get link file info & `fileInfo, err := \seqsplit{os.Lstat("test\_sym.txt")`} \tn 
% Row Count 6 (+ 2)
% Row 3
\SetRowColor{white}
change link file owner & `err := \seqsplit{os.Lchown("test\_sym.txt"}, uid, gid)` \tn 
% Row Count 8 (+ 2)
% Row 4
\SetRowColor{LightBackground}
read a link & `dest, err := \seqsplit{os.ReadLink("link\_file.txt")`} \tn 
% Row Count 10 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{8.4cm}}{A hard link creates a new pointer to the same place. A file will only be deleted from disk after all links are removed. Hard links only work on the same file system. A hard link is what you might consider a 'normal' link. \newline  \newline A symbolic link, or soft link, only reference other files by name. They can point to files on different filesystems. Not all systems support symlinks.}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{3.04 cm} x{4.96 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Read and Write}}  \tn
% Row 0
\SetRowColor{LightBackground}
write bytes to file & `n, err := file.Write({[}{]}byte("hello, world!\textbackslash{}n"))` \tn 
% Row Count 3 (+ 3)
% Row 1
\SetRowColor{white}
write string to file & `n, err := file.WriteString("Hello, world!\textbackslash{}n")` \tn 
% Row Count 5 (+ 2)
% Row 2
\SetRowColor{LightBackground}
write at offset & `n, err := file.WriteAt({[}{]}byte("Hello"), 10)` \tn 
% Row Count 7 (+ 2)
% Row 3
\SetRowColor{white}
read to byte & `n, err := file.Read(byteSlice)` \tn 
% Row Count 9 (+ 2)
% Row 4
\SetRowColor{LightBackground}
read exactly n bytes & `n, err := io.ReadFull(file, byteSlice)` \tn 
% Row Count 11 (+ 2)
% Row 5
\SetRowColor{white}
read at least n bytes & `n, err := io.ReadAtLeast(file, byteSlice, minBytes)` \tn 
% Row Count 14 (+ 3)
% Row 6
\SetRowColor{LightBackground}
read all bytes of a file & `byteSlice, err := ioutil.ReadAll(file)` \tn 
% Row Count 16 (+ 2)
% Row 7
\SetRowColor{white}
read from offset & `n, err := file.ReadAt(byteSlice, 10)` \tn 
% Row Count 18 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{3.44 cm} x{4.56 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Work with directories}}  \tn
% Row 0
\SetRowColor{LightBackground}
create a directory & `err := os.Mkdir("myDir", 0600)` \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
recursively create a directory & `err := \seqsplit{os.MkdirAll("dir/subdir/myDir"}, 0600)` \tn 
% Row Count 5 (+ 3)
% Row 2
\SetRowColor{LightBackground}
delete a directory recursively & `err := os.RemoveAll("dir/")` \tn 
% Row Count 7 (+ 2)
% Row 3
\SetRowColor{white}
list directory files & `fileInfo, err := ioutil.ReadDir(".")` \tn 
% Row Count 9 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{2.64 cm} x{5.36 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Shortcuts}}  \tn
% Row 0
\SetRowColor{LightBackground}
quick read from file & `byteSlice, err := \seqsplit{ioutil.ReadFile("test.txt")`} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
quick write to file & `err := \seqsplit{ioutil.WriteFile("test.txt"}, {[}{]}byte("Hello"), 0666)` \tn 
% Row Count 5 (+ 3)
% Row 2
\SetRowColor{LightBackground}
copy file & `n, err := io.Copy(newFile, originFile)` \tn 
% Row Count 7 (+ 2)
% Row 3
\SetRowColor{white}
write string to file & `io.WriteString(file, "Hello, world")` \tn 
% Row Count 9 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{2.32 cm} x{5.68 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Temporary files and directories}}  \tn
% Row 0
\SetRowColor{LightBackground}
create temp dir & `ioutil.TempDir(dir, prefix string) (name string, err error)` \tn 
% Row Count 3 (+ 3)
% Row 1
\SetRowColor{white}
create temp file & `ioutil.TempFile(dir, prefix string) (f *os.File, err error)` \tn 
% Row Count 6 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{References}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{8.4cm}}{\{\{link="http://devdungeon.com/content/working-files-go"\}\}Working with Files in Go\{\{/link\}\}} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\mymulticolumn{1}{x{8.4cm}}{\{\{link="https://golang.org/pkg/os/"\}\}golang `os` standard library\{\{/link\}\}} \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{8.4cm}}{\{\{link="https://golang.org/pkg/io/ioutil"\}\}golang `ioutil` standard library\{\{/link\}\}} \tn 
% Row Count 6 (+ 2)
% Row 3
\SetRowColor{white}
\mymulticolumn{1}{x{8.4cm}}{\{\{link="https://golang.org/pkg/io"\}\}golang `iou` standard library\{\{/link\}\}} \tn 
% Row Count 8 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}


% That's all folks
\end{multicols*}

\end{document}