casso@casso-ThinkPad-T61p:~/tmp$ cat test.sh
#!/bin/bash

while read line; do
    echo "$line;$2;$3" >> out.txt
done < $1
casso@casso-ThinkPad-T61p:~/tmp$ cat in.txt
a.b.c.d
w.e.r.tcasso@casso-ThinkPad-T61p:~/tmp$ ./test.sh in.txt 10.0.0.1 255.255.255.0
casso@casso-ThinkPad-T61p:~/tmp$ cat out.txt
a.b.c.d;10.0.0.1;255.255.255.0
a.b.c.d;10.0.0.1;255.255.255.0
a.b.c.d;10.0.0.1;255.255.255.0
casso@casso-ThinkPad-T61p:~/tmp$