bashline.sty — simple implementation of command line calls for [Xe]LaTeX.

bashline.sty

% !TeX encoding = UTF-8
\ProvidesPackage{bashline}[2016/10/24 v. 0.1]

\makeatletter
    \newcommand{\bashline@file@name}[1]{%
        /tmp/${USER}-${HOSTNAME}-\jobname-#1.tex%
    }
    \newread\bashline@file
    \newcommand{\bashline@command@one}[2][tmp]{%
        \immediate\write18{#2 > \bashline@file@name{#1}}
        \openin\bashline@file=\bashline@file@name{#1}
        % The group localizes the change to \endlinechar
        \bgroup
            \endlinechar=-1
            \read\bashline@file to \localline
            % Since everything in the group is local, 
            % we have to explicitly make the assignment global
            \global\let\bashline@result\localline
        \egroup
        \closein\bashline@file
        % Clean up after ourselves
        \immediate\write18{rm \bashline@file@name{#1}}
        \bashline@result
    }
    \newcommand{\bashline@command@many}[2][tmp]{%
        \immediate\write18{#2 > \bashline@file@name{#1}}
        \openin\bashline@file=\bashline@file@name{#1}
        % The group localizes the change to \endlinechar
        \newcount\linecnt
        \bgroup
            \endlinechar=-1
            \loop\unless\ifeof\bashline@file 
                \read\bashline@file to \localline%
                \localline
                \newline
            \repeat
        \egroup
        \closein\bashline@file
        % Clean up after ourselves
        \immediate\write18{rm \bashline@file@name{#1}}
    }
    \newcommand{\bashline}[2][tmp]{%
        \bashline@command@one[#1]{#2}%
    }
    \newcommand{\bashlines}[2][tmp]{%
        \bashline@command@many[#1]{#2}%
    }
\makeatother

\newcommand{\urandomstring}[1]{%
    \bashline{cat /dev/urandom | tr -dc "A-Za-z0-9" | fold -c#1 | head -1}%
}

\newcommand{\bashdate}{%
    \bashline{date --iso-8601}%
}

\newcommand{\bashdatetime}{%
    \bashline{date --iso-8601=seconds}%
}

\newcommand{\commit}{%
    \bashline{git describe --dirty }%
}

\newcommand{\commitlog}{%
    \bashline{git log -1 --oneline}%
}

\newcommand{\branch}{%
    \bashline{git describe --all}%
}

\endinput