How to merge pdf file in command-line
pdfunite pdf1.pdf pdf2.pdf out.pdf
pdfunite ~/my_repos/raveenkumar.xyz/Blog/linux_and_programming/vimrefcard.pdf ~/my_repos/raveenkumar.xyz/Blog/linux_and_programming/vimrefcard.pdf 2022-10-19-out.pdf
pdfunite pdf1.pdf pdf2.pdf out.pdf
pdfunite ~/my_repos/raveenkumar.xyz/Blog/linux_and_programming/vimrefcard.pdf ~/my_repos/raveenkumar.xyz/Blog/linux_and_programming/vimrefcard.pdf 2022-10-19-out.pdf