I wanted a quick and convenient cheatsheet to use with Vim. Additionally, it needed to be dynamic such that it only included the things I was trying to learn. And once those things were ingrained in my fingertips, there should be a way to remove the tips (the cheatsheet tips, not my fingertips) from my cheatsheet. And ideally, adding and deleting tips from my cheatsheet should be quick and relatively effortless. That’s when I came upon the idea of having my screen background become my cheatsheet.
Concatenate PDF’s on the Command Line
I used to use pdfchain to concatenate PDF files. It’s a GUI based program that gets the job done and can do a few other things as well.
But for simple concatenating jobs, it’s just easier, and quicker, to use the command line.
There’s a couple of programs that I routinely use: gs (ghostscript) and pdftk.
Clarifying bash redirection for stdout and stderr
I sometimes forget some of the simplier things that I actually use quite frequently in the bash shell. Error redirection involving stdout and stderr seems to be one of them. Below are a few examples that explain things better than I can put in words. But first, note the following givens and assumptions:
stdout== standard output == file descriptor 1
stderr== standard error == file descriptor 2
&indicates that what follows is a file descriptor and not a file name
/notis a non-existent directory
/tmpis an existing directory