@@ -632,6 +635,8 @@ Words resulting from \emph{word splitting} (\ref{word-splitting}) and containing
A pattern expands to the list of matching filenames, if any; otherwise it
remains unchanged.
Several \textit{options} (\ref{options}) can modify this behaviour.
\hypertarget{quote-removal}{%
\subsection{Quote Removal}\label{quote-removal}}
...
...
@@ -888,7 +893,7 @@ arguments with \emph{shell arithmetic} (\ref{shell-arithmetic}).
% TODO: mention that globbing occurs only if the RHS of == is unquoted.
% TODO: remind that expansion occurs (except W F)
\begin{tabular}{ll}
\begin{tabular}{lp{5cm}}
\textbf{expr}&\textbf{true iff}\\
\texttt{-e f}&\texttt{f} exists \\
\texttt{-f f}&\texttt{f} is a regular file \\
...
...
@@ -903,6 +908,7 @@ arguments with \emph{shell arithmetic} (\ref{shell-arithmetic}).
\texttt{str}&\texttt{str} has nonzero length \\
\texttt{s == p}&\texttt{s} =/matches \texttt{p}\\
\texttt{s = p}&\texttt{s} =/matches \texttt{p}\\
\texttt{s =\~{} re}&\texttt{s} matches POSIX extended regular expression \ttit{re}, any matches and captures are stored in array \texttt{BASH\_REMATCH}\\
\texttt{s != p}&\texttt{s}$\neq$/doesn't match \texttt{p}\\
\texttt{s1 < s2}&\texttt{s1} sorts before \texttt{s2} (\texttt{>}: after) \\
\texttt{a1 -eq a2}&\texttt{a1}$=$\texttt{a2}\\
...
...
@@ -1145,6 +1151,40 @@ global)
\hypertarget{options}{%
\section{Options}\label{options}}
A selection of options useful for programming
\subsection{\texttt{set} Options}\label{opt-set}
The following options can be set with \texttt{set -\ttit{o}} (short
form) or \texttt{set -o \ttit{option}} (long form); they can also be set
with \texttt{shopt -s -o \ttit{option}}. To unset: \texttt{set
+\ttit{o}}, \texttt{set +o \ttit{option}}, or \texttt{shopt -u -o
\ttit{option}}, respectively.
\begin{tabular}{p{2.5cm}p{5.5cm}}
\texttt{-e}, \texttt{-o~errexit}& Exit immediately if a command returns nonzero status (the \href{https://www.gnu.org/software/bash/manual/html_node/The-Set-Builtin.html}{complete rules} are more complicated). \\
\texttt{-f}, \texttt{-o~noglob}& Do not peform filename expansion (\ref{filename-expansion}). \\
\texttt{-n}, \texttt{-o~noexec}& Read input but do not execute commands ("dry run"). \\
\texttt{-u}, \texttt{-o~nounset}& Treat unset parameters (other than \texttt{@} and \texttt{*}) during expansion (\ref{parameter-expansion}) as an error. \\
\texttt{-x}, \texttt{-o~xtrace}& Print a trace of commands (\eg{} for debugging). \\
\texttt{-B}, \texttt{-o~braceexpand}& Perform brace expansion (ON by default). \\
\texttt{-C}, \texttt{-o~noclobber}& Prevent redirection (\ref{redirections}) from overwriting files. \\
The following options can be set by \texttt{shopt -s \ttit{opt}}, and unset by
\texttt{shopt -u \ttit{opt}}.
\begin{tabular}{lp{6cm}}
\texttt{dotglob}& If set, globbing considers files with names starting in '\texttt{.}' (except '\texttt{.}' and '\texttt{..}', which never match globs) If unset, these files don't match. \\
\texttt{failglob}& Patterns that fail to match during filename globbing (\ref{filename-expansion}) cause an error \\
\texttt{globstar}& During filename expansion (\ref{filename-expansion}), \texttt{**} recursively matches filenames into subdirectories (\texttt{**/}: only directories) \\
\texttt{nocaseglob}& Filename expansion (\ref{filename-expansion}) is case-insensitive \\
\texttt{nocasematch}& Pattern matching in \texttt{case} (\ref{case---in}) and \texttt{[[...]]} (\ref{dsb-cond}) is case-insensitive. \\
\texttt{nullglob}& Filename patterns (\ref{filename-expansion}) which match no files expand to the null string. \\
\texttt{xpg\_echo}& The \texttt{echo} builtin expands \texttt{\textbackslash}-escape sequences. \\
\end{tabular}
\hypertarget{references}{%
\section{References}\label{references}}
...
...
@@ -1179,11 +1219,11 @@ global)
\begin{itemize}
\item\texttt{read x y \textless{}\textless(\ldots)} (use process substitution to set variables)
\item\texttt{\$(\textless{}\ file)} is a faster equivalent of \texttt{\$(cat\ file)}
\item using \texttt{trap} to ensure closing files and
cleaning up
\end{itemize}
\item
\texttt{f -o a1 a2} -- you can pass switches and options to functions
