Because I always forget this awk command

[chicks_dig_unix]

awk -F":" ' $3 < 500 && $3 > 100 ' /etc/passwd | cut -d ':' -f3 > /tmp/ftp_add
A=` sort -g /tmp/ftp_add | tail -1`
A=`expr $A + 1`
rm /tmp/ftp_add