一个shell，拼字符

cat code.txt
a
b
c
d
....
要求输出：
"a=",$a,"\n",
"b=",$b,"\n",
......

for i in `cat code.txt`;do echo \"$i=,\"'$'$i,'"\n"',;done

sed 's/^\(.*\)$/"\1=",$\1,"\\n",/g' code.txt