C:\Program Files\Windows Resource Kits\Tools>findstr /?
Searches for strings in files.

FINDSTR [/B] [/E] [/L] [/R] [/S] [/I] [/X] [/V] [/N] [/M] [/O] [/P] [/F:file]
[/C:string] [/G:file] [/D:dir list] [/A:color attributes] [/OFF[LINE]]
strings [[drive:][path]filename[ …]]

/B         Matches pattern if at the beginning of a line.
/E         Matches pattern if at the end of a line.
/L         Uses search strings literally.
/R         Uses search strings as regular expressions.
/S         Searches for matching files in the current directory and all
subdirectories.
/I         Specifies that the search is not to be case-sensitive.
/X         Prints lines that match exactly.
/V         Prints only lines that do not contain a match.
/N         Prints the line number before each line that matches.
/M         Prints only the filename if a file contains a match.
/O         Prints character offset before each matching line.
/P         Skip files with non-printable characters.
/OFF[LINE] Do not skip files with offline attribute set.
/A:attr    Specifies color attribute with two hex digits. See “color /?”
/F:file    Reads file list from the specified file(/ stands for console).
/C:string  Uses specified string as a literal search string.
/G:file    Gets search strings from the specified file(/ stands for console).
/D:dir     Search a semicolon delimited list of directories
strings    Text to be searched for.
[drive:][path]filename
Specifies a file or files to search.

Use spaces to separate multiple search strings unless the argument is prefixed
with /C.  For example, ‘FINDSTR “hello there” x.y’ searches for “hello” or
“there” in file x.y.  ‘FINDSTR /C:”hello there” x.y’ searches for
“hello there” in file x.y.

Regular expression quick reference:
.        Wildcard: any character
*        Repeat: zero or more occurances of previous character or class
^        Line position: beginning of line
$        Line position: end of line
[class]  Character class: any one character in set
[^class] Inverse class: any one character not in set
[x-y]    Range: any characters within the specified range
\x       Escape: literal use of metacharacter x
\<xyz    Word position: beginning of word
xyz\>    Word position: end of word

For full information on FINDSTR regular expressions refer to the online Command
Reference.

netstat -ano | findstr LISTENING

TCP    0.0.0.0:7              0.0.0.0:0              LISTENING       1596
TCP    0.0.0.0:9              0.0.0.0:0              LISTENING       1596
TCP    0.0.0.0:13             0.0.0.0:0              LISTENING       1596
TCP    0.0.0.0:17             0.0.0.0:0              LISTENING       1596
TCP    0.0.0.0:19             0.0.0.0:0              LISTENING       1596
TCP    0.0.0.0:21             0.0.0.0:0              LISTENING       1848
TCP    0.0.0.0:135            0.0.0.0:0              LISTENING       904