php - How to multiple regexes into one regex -

hi have 3 regex preg_match in 1 if..

i want know if it's possible mix 3 regex in 1?

this if 3 regex :

if(!preg_match("#\s#",$file) && !preg_match("#\.\.\/#",$file) && (preg_match_all("#/#",$file,$match)==1)):

(i want: no "space" , no "../" , 1 "/")

thanks help.

edit

add needed in list point (more readable):

it's quite simple. let's start step step crafting regex:

first of all, let's use anchors define begin&end of string: ^$
i want: no "space", we've got \s matches non-white space character: ^\s+$
no "../", let's add negative lookahead ^(?!.*[.][.]/)\s+$, note don't need escape dot inside character class. forwardslash, we'll use different delimiters
one optional "/", add negative lookahead prevents 2 forwardslashes ^(?!(?:.*/){2})(?!.*[.][.]/)\s+$
let's define delimiters , add s modifier match newlines .: ~^(?!(?:.*/){2})(?!.*[.][.]/)\s+$~s , here go online demo

GHI