[root@zejin240 chenzejin]# cat 1.sh 
hello world 2016
better
[root@zejin240 chenzejin]# a=(cat .sh)

[root@zejin240 chenzejin]# b=(`cat .sh`)

[root@zejin240 chenzejin]# c=$(cat .sh)

[root@zejin240 chenzejin]# d=`cat .sh`

[root@zejin240 chenzejin]# echo ${a[@]}

cat .sh

[root@zejin240 chenzejin]# echo ${b[@]}

hello world  better

[root@zejin240 chenzejin]# echo ${c[@]}

hello world  better

[root@zejin240 chenzejin]# echo ${d[@]}

hello world  better

[root@zejin240 chenzejin]# echo $a

cat

[root@zejin240 chenzejin]# echo $b

hello

[root@zejin240 chenzejin]# echo $c

hello world  better

[root@zejin240 chenzejin]# echo $d

hello world  better

[root@zejin240 chenzejin]# e=$(`cat 1.sh`)
-bash: hello: command not found