Is $(...)
the same as (...)
in Bash?
Also, is $((...))
the same as ((...))
?
Also, is ${...}
the sa
Adding to the answer above:
[..]
is used in conditions or logical expressions. Example:$ VAR=2
$ if [ $VAR -eq 2 ]
> then
> echo 'yes'
> fi
yes
[[...]]
offers extended functionality to single square brackets. Particularly, it is useful for =~ operator (used in regular expressions). Example:$ VAR='some string'
$ if [[ $VAR =~ [a-z] ]]; then
> echo 'is alphabetic'
> fi
is alphabetic
Reference:
https://linuxconfig.org/bash-scripting-parenthesis-explained