I stumbled upon a colleague’s bash script which contained the following line, which in isolation, made not much sense to me.
WRKDIR=~/app/work$$
But after some googling and having a look at the complete scope of the script, I finally got it.
...
WRKDIR=~/app/work$$
...
mkdir $WRKDIR
...
...
...
...
rmdir $WRKDIR
$$is a reference to the PID (process id)- it was used to create a unique temporary file
All good?
Well, there may be a couple of reasons why this is not good.
At first and foremost, it is a bit obscure - at least for people who do not work a lot with bash.
Consider the alternative: mktemp
No matter from which programming language you come, you will understand that.
Also, there are a couple of hints out there,
why mkdir foo$$ may be not a good idea:
- security problems
- race conditions
- other stuff
… but no really good and detailed explanation. Can you bring light into the darkness?
Create a pull request or drop me a note via email or twitter, see https://jugmac00.github.io/