Linux 中awk语句匹配首个数字与匹配首个连续的数字的区别

001、

[root@localhost test]# cat b.txt                   ## 测试数据
0001    20081223efs333kjfdj     EREADFASDLKJCV
0002    20081208djfks2288daa    JDKFJALSDJFsddf
0003    20081208efskjfdj        EREADFASDLKJCV
0004    20081211djfksdaa1234    JDKFJALSDJFsddf
[root@localhost test]# awk '{sub("[0-9]", "", $2); print $0}' b.txt          ## 匹配首个数字
0001 0081223efs333kjfdj EREADFASDLKJCV
0002 0081208djfks2288daa JDKFJALSDJFsddf
0003 0081208efskjfdj EREADFASDLKJCV
0004 0081211djfksdaa1234 JDKFJALSDJFsddf
[root@localhost test]# awk '{sub("[0-9]+", "", $2); print $0}' b.txt         ## 匹配首个连续的数字
0001 efs333kjfdj EREADFASDLKJCV
0002 djfks2288daa JDKFJALSDJFsddf
0003 efskjfdj EREADFASDLKJCV
0004 djfksdaa1234 JDKFJALSDJFsddf

 。

002、

[root@localhost test]# cat b.txt                                         ## 测试数据
0001    20081223efs333kjfdj     EREADFASDLKJCV
0002    20081208djfks2288daa    JDKFJALSDJFsddf
0003    20081208efskjfdj        EREADFASDLKJCV
0004    20081211djfksdaa1234    JDKFJALSDJFsddf
[root@localhost test]# awk '{sub(/[0-9]/, "", $2); print $0}' b.txt      ## 第二行匹配数个数字
0001 0081223efs333kjfdj EREADFASDLKJCV
0002 0081208djfks2288daa JDKFJALSDJFsddf
0003 0081208efskjfdj EREADFASDLKJCV
0004 0081211djfksdaa1234 JDKFJALSDJFsddf
[root@localhost test]# awk '{sub(/[0-9]+/, "", $2); print $0}' b.txt      ## 匹配第二行首个连续的数字
0001 efs333kjfdj EREADFASDLKJCV
0002 djfks2288daa JDKFJALSDJFsddf
0003 efskjfdj EREADFASDLKJCV
0004 djfksdaa1234 JDKFJALSDJFsddf

 。