Handy bash one liner to grep all port numbers from an Nmap output file and print them to a single line for further scanning.

cat nmap/scan1.nmap | grep -oP '^\d+/tcp' | awk -F/ '{print $1}' | tr '\n' ',' | sed 's/,$/\n/'

Breakdown of the Command:

cat nmap/scan1.nmap: Reads the Nmap output file. grep -oP '^\d+/tcp': Uses grep with Perl-compatible regex (-P) to extract lines starting with port numbers followed by /tcp. awk -F/ '{print $1}': Splits the output by / and prints the first part (the port number). tr '\n' ',': Translates newlines into commas. sed 's/,$/\n/': Uses sed to remove the trailing comma and replace it with a newline.

Example Output:

For the given input, the command will output:

21,22,23,25,53,80,111,139,445,512,513,514,1099,1524,2049,2121,3306,3632,5432,5900,6000,6667,6697,8009,8180,8787,38405,45023,46534,47247