^cell\d :

^[1-9]\d+$

^：表示匹配起始位置

\d+: 0-9的数字，个数为任意个

$: 匹配末尾

. : any character

[abc] : any of the characters a,b,or c (same as a|b|c)

[abc[hij]]: any of a,b,c,h,j,j (same as a|b|c|h|i|j) (union)

[a-z&&[hij]]: either h,I, or j (insersection)

\s : a whitespace character (space, tab, newline, form feed, carriage return)

\S : a non-whitespace character ([^\s])

\d : a numberic digit [0-9]

\D : a non-digit [0-9]

\w : a word character [a-zA-Z_0-9]

\W : a non-word chacter [^\w]

正则表达式的百度百科详细解释link