How to do a circular shift of strings in bash?

A few tidbits that should help: when you call a function with a string, the string is split into multiple arguments (the positional parameters, named $n, where n are integers starting at 1) on the characters in the variable $IFS (which defaults to spaces, tabs and newlines)

function first() {
    echo $1
}
first one two three
# outputs: "one"

$* and $@ give you all the positional parameters, in order.

Second, the special variable $# holds the number of arguments to a function.

Third, shift discards the first positional parameter and moves up all the others by one.

function tail() {
    shift
    echo $*
}

Fourth, you can capture the output of commands and functions using `...` or $(...)

rest=`tail $*`

Fifth, you can send the output of one command to the input of another using the pipe character (|):

seq 5 | sort

To get you started, check out the read builtin:

while read first_word rest_of_the_line; do
    ... your code here ...
done

You also need a way to feed your input file into that loop.

Let me allow to show you a quick working example based on @outis answer:

strings="string1 string2 string3"
next() { echo $1; }
rest() { shift; echo $*; }
for i in $strings; do
  echo $(next $strings)
  strings=$(rest $strings)
done

Or other way-round if you're interested in traversing by sequence:

strings="string1 string2 string3"
next() { echo $1; }
rest() { shift; echo $*; }
totalWords=$(c() { echo $#; }; c $strings)
for i in `seq -w 1 $totalWords`; do
  echo $i: $(next $strings)
  strings=$(rest $strings)
done