Use “<“ and “>” in an action.conf

[dBsooner]

Is it possible to use less than (<) and greater than (>) symbols in an action.conf? I’m trying to setup a Discord notification system posting to webhooks (Discord API). In order for URLs to not show previews on Discord, they have to be wrapped in <>. Which, I assume is strictly for use by fail2ban as variable usage. Is there a way to escape the <>?

[sebres]

Is it possible to use less than (<) and greater than (>) symbols in an action.conf?

Yes it is... Only available tags <token>, where token normally contains alphanumeric, underscore and minus characters, will be replaced recursively (so <primary-<secondary>> form too. Regex for tokens looks like

fail2ban/fail2ban/helpers.py

Line 350 in 8eac5f5

TAG_CRE = re.compile(r'<([^ <>]+)>')

If you use < and > alone (e. g. separated by spaces from rest of the command, they will be ignored).

Is there a way to escape the <``>?

Yes, one could add something like that in definition or default section:

[DEFAULT]
lt = <
gt = >

And then use <lt> or %(lt)s for < char and <gt> or %(gt)s for > char.
But as already said it is unneeded, if you write it like cmd 1>some-log 2>&1 <<< "some stdin" (e. g. with a space delimiter before or after), they will be never considered as part of tags.
The only possible ambiguous way will be something like this - cmd <file-in>file-out, because then file-in can be considered as a token, if such parameter or variable gets declared in conf-file or its includes.
However nobody really writes it in this way, rather somehow like this (with a space in between, so fully safe):

- cmd <file-in>file-out
+ cmd <file-in >file-out

[dBsooner]

Perfect, Thank you!