How to split a line into words separated by one or more spaces in bash?

s='foo bar baz'
a=( $s )
echo ${a[0]}
echo ${a[1]}
...

It depends upon what you mean by split. If you want to iterate over words in a line, which is in a variable, you can just iterate. For example, let's say the variable line is this is a line. Then you can do this:

for word in $line; do echo $word; done

This will print:

this
is
a
line

for .. in $var splits $var using the values in $IFS, the default value of which means "split blanks and newlines".

If you want to read lines from user or a file, you can do something like:

cat $filename | while read line
do
    echo "Processing new line" >/dev/tty
    for word in $line
    do
        echo $word
    done
done

For anything else, you need to be more explicit and define your question in more detail.

Note: Edited to remove bashism, but I still kept cat $filename | ... because I like it more than redirection.

do this

while read -r line
do
  set -- $line
  echo "$1 $2"
done <"file"

$1, $2 etc will be your 1st and 2nd splitted "fields". use $@ to get all values..use $# to get length of the "fields".

$ line="these are words"
$ ll=($line)
$ declare -p ll  # dump the array
declare -a ll='([0]="these" [1]="are" [2]="words")'
$ for w in ${ll[@]}; do echo $w; done
these
are
words

The -a option of read will allow you to split a line read in by the characters contained in $IFS.

If you already have your line of text in a variable $LINE, then you should be able to say

for L in $LINE; do
   echo $L;
done