Create a PDF file

_$: man -t ls > ls.ps && ps2pdf ls.ps ls.pdf

Example: Generate a PDF file with all git man pages to read at lunchtime and be the coolest guy in the restaurant.

_$: for i in /usr/share/man/man1/git*
do
  filename=$(basename $i .1.gz)
  man -t ${filename} > /tmp/git/${filename}.ps
  ps2pdf /tmp/git/${filename}.ps /tmp/git/${filename}.pdf
  rm /tmp/git/${filename}.ps
done

In one file:

_$: gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=the-git-man.pdf /tmp/git/*.pdf