$re = '/(?<test>^\s+\K(umac|hmac)[\w\-\.@]+)/m';
$str = ' kex_algorithms: (8)
curve25519-sha256@libssh.org
ecdh-sha2-nistp256
ecdh-sha2-nistp384
ecdh-sha2-nistp521
diffie-hellman-group-exchange-sha256
diffie-hellman-group-exchange-sha1
diffie-hellman-group14-sha1
diffie-hellman-group1-sha1
server_host_key_algorithms: (4)
ssh-rsa
ssh-dss
ecdsa-sha2-nistp256
ssh-ed25519
encryption_algorithms: (14)
aes128-ctr
aes192-ctr
aes256-ctr
arcfour256
arcfour128
chacha20-poly1305@openssh.com
aes128-cbc
3des-cbc
blowfish-cbc
cast128-cbc
aes192-cbc
aes256-cbc
arcfour
rijndael-cbc@lysator.liu.se
mac_algorithms: (19)
hmac-md5-etm@openssh.com
hmac-sha1-etm@openssh.com
umac-64-etm@openssh.com
umac-128-etm@openssh.com
hmac-sha2-256-etm@openssh.com
hmac-sha2-512-etm@openssh.com
hmac-ripemd160-etm@openssh.com
hmac-sha1-96-etm@openssh.com
hmac-md5-96-etm@openssh.com
hmac-md5
hmac-sha1
umac-64@openssh.com
umac-128@openssh.com
hmac-sha2-256
hmac-sha2-512
hmac-ripemd160
hmac-ripemd160@openssh.com
hmac-sha1-96
hmac-md5-96
compression_algorithms: (2)
none
zlib@openssh.com"';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php