Bash set

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External

Internal

set and Positional Parameters

arg="a b c"
set ${arg}

assigns "a", "b", "c" to positional parameters $1, $2 and $3.

Note that if any of the space-separated argument contains '--', set will try to interpret that sequence of characters:

set: --: invalid option

so in order to turn it back into positional argument, you will have to ??? do something, did not figure it out yet.

List Separator

The default list separator is space. That can be changed by setting the value of the IFS variable before executing set.

Example:

arg="a,b,c"
IFS=","
set ${arg}

will identically assign "a", "b", "c" to positional parameters $1, $2 and $3.

Note you must set IFS back to whitespace after setting it to something else, so the basic shell function work as expected. This is done as shown here: restoring the default IFS value.

For more details about IFS see:

IFS