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regexlinuxgreprtmpngrep

Regular Expression - search until specific string appears

I'm using ngrep and grep to extract some strings out of network traffic:

sudo ngrep -W byline | grep...

Now I want grep to search for a string and copy from first letter on until some different string appears. Strings are rtmp and .. For example:

"fwef-$*nVrtmp://Ggdggragravrv.com/lolwtf.mp5skill0rz%%&:/getr4kt..Glub"

should turn into:

"rtmp://Ggdggragravrv.com/lolwtf.mp5skill0rz%%&:/getr4kt"

Is this possible in any way?

Solution

  • You could try the below grep command which uses a positive lookahead based regex,

    $ echo "fwef-$*nVrtmp://Ggdggragravrv.com/lolwtf.mp5skill0rz%%&:/getr4kt..Glub" | grep -oP 'rtmp.*?(?=\.\.)'
rtmp://Ggdggragravrv.com/lolwtf.mp5skill0rz%%&:/getr4kt