man ??

write txt\gun.txt $2-
/notice $nick " $+ $2- $+ " is add too txt\gun.txt
if ( $2 == $null ) {
/notice $nick 2The correct way too add text is: 5 !add_gun < text >
}

is better use this

if ( $2- != $null ) {
write txt\gun.txt $2-
/notice $nick " $+ $2- $+ " is add too txt\gun.txt
}
else {
/notice $nick 2The correct way too add text is: 5 !add_gun < text >
}