I need to fill the page (100%) with the watermark text repeated and rotated under 45 degrees. I should to do it for every page in document. This code works good, but in this case I have only one watermark at center.
\documentclass{article}
\usepackage{tikz}
\usepackage{pdfpages}
\pagestyle{empty}
\newcommand{\filename}{/home/Documents/c.pdf}
\newcommand{\watermark}{\tikz[remember picture, overlay] \node [black,opacity=0.1,rotate=45,scale=4.0] at (current page.north west) {This is watermark text to repeat again and again} -- (current page.south east);}
\begin{document}
\foreach \index in {1,...,\the\pdflastximagepages}
{
\includepdf[pages=\index,pagecommand={\watermark}]{\filename}
}
\end{document}
Any ideas or suggestions are welcome?
Thank you for your time and help.

\foreach \pos in {...}to set the node on path(current page.north west) -- node[pos=\pos, ...] {...} -- (current page.south east)and use the trick in https://tex.stackexchange.com/questions/219478/how-to-include-multiple-pdf-pages-using-foreach-as-tikzpicture – ZhiyuanLck Jun 03 '20 at 14:02