$re = '/M(\d{1,3})[-_]\d{1,4}(CCU?|)/m';
$str = 'DOA000281_ICS_U-M1-300_R-Zero_S.TAB
DOA000281_ICS_U-M10-300_R-Zero_S.TAB
DOA000281_ICS_U-M100-300_R-Zero_S.TAB
DOA000281_ICS_U-M2-300_R-Zero_S.TAB
DOA000281_ICS_U-M200-300CCU_R-Zero_S.TAB
DOA000281_ICS_U-M200-300_R-Zero_S.TAB
DOA000281_ICS_U-M30-300CCU_R-Zero_S.TAB
DOA000281_ICS_U-M30-300_R-Zero_S.TAB
DOA000281_ICS_U-M5-300_R-Zero_S.TAB
DOA000281_ICS_U-M50-300_R-Zero_S.TAB
DOA_000533_ICS_100y180s_0y0sMax.tab
DOA_000533_ICS_10y180s_0y0sMax.tab
DOA_000533_ICS_1y180s_0y0sMax.tab
DOA_000533_ICS_200ccy180s_0y0sMax.tab
DOA_000533_ICS_200y180s_0y0sMax.tab
DOA_000533_ICS_2y180s_0y0sMax.tab
DOA_000533_ICS_30ccy180s_0y0sMax.tab
DOA_000533_ICS_30y180s_0y0sMax.tab
DOA_000533_ICS_50y180s_0y0sMax.tab
DOA_000533_ICS_5y180s_0y0sMax.tab
CFA_AUG2018_2D DOA_000537_ICS_100y600s_0y0sMax.TAB
CFA_AUG2018_2D DOA_000537_ICS_10y600s_0y0sMax.TAB
CFA_AUG2018_2D DOA_000537_ICS_1y600s_0y0sMax.TAB
CFA_AUG2018_2D DOA_000537_ICS_200ccy600s_0y0sMax.TAB
CFA_AUG2018_2D DOA_000537_ICS_200y600s_0y0sMax.TAB
CFA_AUG2018_2D DOA_000537_ICS_2y600s_0y0sMax.TAB
CFA_AUG2018_2D DOA_000537_ICS_30ccy600s_0y0sMax.TAB
CFA_AUG2018_2D DOA_000537_ICS_30y600s_0y0sMax.TAB
CFA_AUG2018_2D DOA_000537_ICS_50y600s_0y0sMax.TAB
CFA_AUG2018_2D DOA_000537_ICS_5y600s_0y0sMax.TAB
DOA000557_ICS_U-M1-60_R-Zero_S_2D.TAB
DOA000557_ICS_U-M10-60_R-Zero_S_2D.TAB
DOA000557_ICS_U-M100-60_R-Zero_S_2D.TAB
DOA000557_ICS_U-M2-60_R-Zero_S_2D.TAB
DOA000557_ICS_U-M200-60CCU_R-Zero_S_2D.TAB
DOA000557_ICS_U-M200-60_R-Zero_S_2D.TAB
DOA000557_ICS_U-M30-60CCU_R-Zero_S_2D.TAB
DOA000557_ICS_U-M30-60_R-Zero_S_2D.TAB
DOA000557_ICS_U-M5-60_R-Zero_S_2D.TAB
DOA000557_ICS_U-M50-60_R-Zero_S_2D.TAB
DOA000616_617 ICS U-M1-60_R-ZERO_Summer.TAB
DOA000616_617 ICS U-M10-60_R-ZERO_Summer.TAB
DOA000616_617 ICS U-M100-60_R-ZERO_Summer.TAB
DOA000616_617 ICS U-M2-60_R-ZERO_Summer.TAB
DOA000616_617 ICS U-M200-60CCU_R-ZERO_Summer.TAB
DOA000616_617 ICS U-M200-60_R-ZERO_Summer.TAB
DOA000616_617 ICS U-M30-60CCU_R-ZERO_Summer.TAB
DOA000616_617 ICS U-M30-60_R-ZERO_Summer.TAB
DOA000616_617 ICS U-M5-60_R-ZERO_Summer.TAB
DOA000616_617 ICS U-M50-60_R-ZERO_Summer.TAB
DOA000674_ICS_U_M100_120_R_Zero_S.TAB
DOA000674_ICS_U_M10_120_R_Zero_S.TAB
DOA000674_ICS_U_M1_120_R_Zero_S.TAB
DOA000674_ICS_U_M200_120CCU_R_Zero_S.TAB
DOA000674_ICS_U_M200_120_R_Zero_S.TAB
DOA000674_ICS_U_M2_120_R_Zero_S.TAB
DOA000674_ICS_U_M30_120CCU_R_Zero_S.TAB
DOA000674_ICS_U_M30_120_R_Zero_S.TAB
DOA000674_ICS_U_M50_120_R_Zero_S.TAB
DOA000674_ICS_U_M5_120_R_Zero_S.TAB
DOA002372_ICS_U_M100_120_R_Zero_S_2D.TAB
DOA002372_ICS_U_M10_120_R_Zero_S_2D.TAB
DOA002372_ICS_U_M1_120_R_Zero_S_2D.TAB
DOA002372_ICS_U_M200_120CC_R_Zero_S_2D.TAB
DOA002372_ICS_U_M200_120_R_Zero_S_2D.TAB
DOA002372_ICS_U_M2_120_R_Zero_S_2D.TAB
DOA002372_ICS_U_M30_120CC_R_Zero_S_2D.TAB
DOA002372_ICS_U_M30_120_R_Zero_S_2D.TAB
DOA002372_ICS_U_M50_120_R_Zero_S_2D.TAB
DOA002372_ICS_U_M5_120_R_Zero_S_2D.TAB
';
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