# [Tex/LaTex] Vertical bar with appropriate length

math-mode

I have a scenario in which I need to create a vertical bar that its size is in the length of 3 rows.

My code is:

\begin{align*}
\begin{cases}
x = 2t + 1\\
y = t + 2\\
z = 3
\end{cases}
& \Bigg | \quad t\in \mathbb R
\end{align*}

I'm familiar with the possibility to set its size in centimetres.
Though I prefer to use something similar to \middle.
Problem is that in this case, I don't have \right and \left, so that \middle is meaningless (and yield an error).

Note: I'm using the TexMaths plugin of LibreOffice, which uses the standard latex program.

You can use a \vphantom of the cases environment to adjust the size of \left (or \right) to suit your needs:

\documentclass{article}
\usepackage{amsmath,amssymb}
\begin{document}

\begin{align*}
\begin{cases}
x = 2t + 1 \\
y = t + 2 \\
z = 3
\end{cases}
& \left.\kern-\nulldelimiterspace
\vphantom{\begin{cases}
x = 2t + 1 \\
y = t + 2 \\
z = 3
\end{align*}

\end{document}

I've just duplicated the cases inside a \vphantom (zero-width \phantom) and corrected for the \left. "null" delimiter. Of course, it's not really all than necessary to use align* as there's no multiline equation alignment required:

\documentclass{article}
\usepackage{amsmath,amssymb}
\begin{document}

$\left.\begin{cases} x = 2t + 1 \\ y = t + 2 \\ z = 3 \end{cases} \right| \quad t \in \mathbb{R}$

\end{document}