How do I reference an array in Bash?
Referencing an array variable without a subscript is equivalent to referencing with a subscript of 0. Any reference to a variable using a valid subscript is legal, and bash will create an array if necessary. An array variable is considered set if a subscript has been assigned a value.
What is the difference between $* and $@ in Bash?
The $@ holds list of all arguments passed to the script. The $* holds list of all arguments passed to the script.
What is the difference between $$ and $! In Linux?
$$ gives the process id of the currently executing process whereas $! shows the process id of the process that recently went into background.
What does [@] mean in Bash?
This Bash guide says: If the index number is @ or * , all members of an array are referenced. When I do this: LIST=(1 2 3) for i in “${LIST[@]}”; do echo “example.$ i” done. it gives the desired result: example.1 example.2 example.3.
What’s the difference between quotes and arrays in Bash?
The difference between the two will arise when you try to loop over such an array using quotes. The *notation will return all the elements of the array as a single word result while the @notation will return a value for each element of the Bash array as a separate word.
How to tell difference between two arrays in Bash?
For a symmetric difference like Dennis’s answer, existing tools like comm work, as long as we massage the input and output a bit (since they work on line-based files, not shell variables). Here, we tell the shell to use newlines to join the array into a single string, and discard tabs when reading lines from comm back into an array.
What’s the difference between referencing an array without a subscript?
Referencing an array variable without a subscript is equivalent to referencing the array with a subscript of 0. In other words, if you don’t supply an index with [], you get the first element of the array: To get all the elements of an array, you need to use @ as the index, e.g. $ {foo [@]}.
What are the benefits of using arrays in Bash?
A great benefit of using Bash Arrays is to preserve field separation. Though, to keep that behavior, you must use double quotes as necessary. In absence of quoting, Bash will split the input into a list of words based on the $IFS value which by default contain spaces and tabs.