mjhjmtu

So I'm trying to set up a systemd service in order to launch a set of files on a daily basis (different types of journals) from directories based off the date. For example a todo list for today would be located in:

~/Documents/Journals/2019/1/23/ToDo.md 

Now the easiest thing to do is to put it in a seperate directory, say today, and then have a bash script move it to the appropriate spot after the last modified time is no longer when it was created, or when the size of the file is larger than the template file. But while that would be easier, I was wondering if it would be possible to write a script to return the directory of the file to be piped through the executed command in the service. Something along the lines of:

ExecStart=/usr/bin/atom | /Path/To/Script/Todays_Dir Todo.md 

which would take the file as an argument and return the directory/file path based off the date (the same way the directory and files are being created).

Is this possible, or should I just stick to the already proposed solution?

Yes, you can write directly to the target directory.

You can't really use a pipe directly as part of an ExecStart= command, since systemd doesn't really implement a full shell. But you can invoke a shell explicitly, which would make it work. For example:

ExecStart=/bin/sh -c '/usr/bin/atom | /Path/To/Script/Todays_Dir Todo.md'

But it turns out this is a bit awkward, since Todays_Dir would end up having to run cat to write to the full path of its argument. In effect, you don't really need a pipe here, you just need to determine the name of a directory and run atom with the proper redirect.

Consider instead just implementing everything in a script and running it directly from the systemd unit.

Something like:

#!/bin/bash
set -e # exit on error
dated_dir=$HOME/Documents/Journals/$(date +%Y/%-m/%-d)
mkdir -p "$dated_dir"
exec atom >"$dated_dir/ToDo.md"

And then in the systemd unit:

ExecStart=/Path/To/Script/GenerateMarkdownToTodaysDir.sh

The exec at the end of the shell script makes the shell replace itself with the atom program, so that systemd will end up running atom directly after setup. For this case it's not that important, so it could be omitted (especially if you're interested in doing some kind of post-processing after the atom run.)

You say “I'm trying to assign something along the lines of ExecStart=/usr/bin/atom /home/user/documents/journal/2019/1/23/todo.md”, so the obvious answer is

ExecStart="/usr/bin/atom /home/user/documents/journal/2019/1/23/todo.md"

But I guess this is now what you want.

If the /home/user… comes from the command then you can do

ExecStart="/usr/bin/atom $(command)"

or

ExecStart='/usr/bin/atom "$(command)"'

to lazy evaluate it.