I'm trying to use the watch command in the fish shell.
sudo watch -d "lsof -a -p (pidof myprogram)"
As you can see this valid command substitution syntax for fish. however I get the following error in watch when I run it.
sh: -c: line 0: syntax error near unexpected token '('
sh: -c: line 0: `lsof -a -p (pidof myprogram)'
If I change the command to sh compatible syntax
sudo watch -d "lsof -a -p $(pidof myprogram)"
I get the following error.
$(...) is not supported. In fish, please use '(pidof)'.
fish: sudo watch -d "lsof -a -p $(pidof myprogram)"
Is there a way around this?
In short:
sudo watch -d "lsof -a -p "(pidof myprogram)
I.e. exit the quotes and do the command substitution (without a space in-between, so it'll be directly attached).
There's a bit of a gap in here in that you want the command's output to not be split at all - here it would split it on newline, and make multiple tokens like "lsof -a -p "line1 "lsof -a -p"line2. That shouldn't be an issue in this case, but if you want it, you should use string split0 like
sudo watch -d "lsof -a -p "(pidof myprogram | string split0)
which will only split on NULL-bytes, which aren't allowed in commandline arguments (this is a general unix thing - because arguments to main are passed as NULL-delimited strings without any other indication of length, if they contain NULLs they will be truncated).