When using my netbook, I don't typically have a printer available. My printer is connected to my wife's desktop computer which doesn't stay on all the time, so I can't rely on sharing the printer to the network and sending documents to it through her computer. Moreover, I'm not all that fond of printing things when saving as a PDF will do.

My email client of choice is Mutt. By default, Mutt uses the lpr command to print, which sends the message to the default printer. But I don't want to actually print the message, I'd like a PDF instead. Luckily for me, as with pretty much anything in Mutt, it is possible to change the default behavior and supply a different command to print messages. Below you can see a short shell script I wrote which will create a PDF from the message contents:

#!/usr/bin/env sh
INPUT="$1" PDIR="$HOME/tmp/mutt_print" OPEN_PDF=zathura

# check to make sure that enscript and ps2pdf are both installed
if ! command -v enscript >/dev/null || ! command -v ps2pdf >/dev/null; then
    echo "ERROR: both enscript and ps2pdf must be installed" 1>&2
    exit 1

# create temp dir if it does not exist
if [ ! -d "$PDIR" ]; then
    mkdir -p "$PDIR" 2>/dev/null
    if [ $? -ne 0 ]; then
        echo "Unable to make directory '$PDIR'" 1>&2
        exit 2

tmpfile="`mktemp $PDIR/mutt_XXXXXXXX.pdf`"
enscript --font=Courier8 $INPUT -G2r -p - 2>/dev/null | ps2pdf - $tmpfile
$OPEN_PDF $tmpfile >/dev/null 2>&1 &
sleep 1
rm $tmpfile

The body of the email will be passed to the script by Mutt as the first argument, or $1, which I store in the INPUT variable. Notice that I'm also defining a couple other variables at the top of the script. The first, PDIR, is a directory where the created PDF should be located*. Secondly, I'm defining a command which should be executed to open the PDF once it has been created. I prefer a lightweight PDF viewer called zathura but any PDF viewer (evince, okular, etc.) can be substituted here.

Just below these variable definitions, I make sure that the commmand-line tools I'm using to create the PDF, (enscript and ps2pdf), are installed. There's not much of a reason to try creating the PDF if they're not present, so a helpful reminder printed to stderr will notify you in the event that they are not installed. In most Linux distributions, these tools are found in the enscript and ghostscript packages, respectively.

You may have noticed that I am not using the which command to determine if these commands are in my $PATH. A recent blog entry by Aaron Toponce alerted me to the fact that which is not consistently implemented across platforms, and may not set a proper exit status or write error messages to stderr. POSIX provides a command named command (what else?), which is consistent across platforms. Running it with -v will print the path of the first matching executable in your $PATH and set an exit status of 0. If there is no match, a non-zero (or false) exit status is set. I don't care about the path to the executable, so this output is redirected to /dev/null.

If you would rather use a different font for the PDF, you can find a list of PostScript font names here

When opening the PDF using the pre-defined command, all output is redirected to /dev/null. This is because GUI apps, when run from the command line, will typically print diagnostic messages, warnings, or errors to stdout/stderr. While these messages can be useful for troubleshooting purposes, any output from the script will be displayed in your Mutt window, which will look very ugly. So, this output is discarded.

In order to get Mutt to call the script in place of lpr, you will need to add the following line to your .muttrc file (use the path where you saved the script, of course):

set print_command="$HOME/bin/mutt_print.sh"

Below is an example of how the result will look. If you do not like the layout, you can alter it by passing different parameters to the enscript command. Check the manpage and experiment to find what works best for you.

Example PDF

So, by replacing the print command with this script, instead of printing the message directly, your PDF viewer of choice will display the message for you. If you want to print it out from there, you can do so. I rarely have a need or desire to print, but this at least leaves me that option. If you want to keep the message, you'll need to use your PDF viewer to save a copy of it, because it will be gone once you close the window. Again, choosing to remove the PDF is a personal preference of mine, so the last two lines of the script can be commented out or removed if you'd rather keep the PDFs.

* I could just place it under /tmp, but since emails tend to have sensitive or personally-identifiable information, I prefer to have the temp files located within my home directory, where I can manage directory permissions and keep these files private.