重复发生的答案如下所示
[root@centos6 bin]# grep -A 2 -B 2 "SampleTextFile.txt" /var/log/messages
Nov 10 00:14:54 centos6 kernel: Kernel logging (proc) stopped.
Nov 10 00:14:54 centos6 rsyslogd: [origin software="rsyslogd" swVersion="5.8.10" x-pid="1513" x-info="http://www.rsyslog.com"] exiting on signal 15.
File SampleTextFile.txt
First Line after original SampleTextFile.txt
Nov 12 18:13:48 centos6 kernel: imklog 5.8.10, log source = /proc/kmsg started.
Nov 12 18:13:48 centos6 rsyslogd: [origin software="rsyslogd" swVersion="5.8.10" x-pid="1519" x-info="http://www.rsyslog.com"] start
--
Nov 12 18:14:19 centos6 polkitd[2382]: started daemon version 0.96 using authority implementation `local' version `0.96'
Nov 12 18:14:19 centos6 rtkit-daemon[2388]: Sucessfully made thread 2386 of process 2386 (/usr/bin/pulseaudio) owned by '42' high priority at nice level -11.
File SampleTextFile.txt
Second Line after original SampleTextFile.txt
Nov 12 18:14:19 centos6 pulseaudio[2386]: alsa-util.c: Disabling timer-based scheduling because running inside a VM.
Nov 12 18:14:19 centos6 rtkit-daemon[2388]: Sucessfully made thread 2392 of process 2386 (/usr/bin/pulseaudio) owned by '42' RT at priority 5.
[root@centos6 bin]#
如果我使用-m开关，那么它不显示“AFTER”线......
[root@centos6 bin]# grep -m 1 -A 2 -B 2 "SampleTextFile.txt" /var/log/messages
Nov 10 00:14:54 centos6 kernel: Kernel logging (proc) stopped.
Nov 10 00:14:54 centos6 rsyslogd: [origin software="rsyslogd" swVersion="5.8.10" x-pid="1513" x-info="http://www.rsyslog.com"] exiting on signal 15.
File SampleTextFile.txt
[root@centos6 bin]#
我的grep版本如下：
[root@centos6 bin]# grep -V
grep (GNU grep) 2.20
Copyright (C) 2014 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Written by Mike Haertel and others, see <http://git.sv.gnu.org/cgit/grep.git/tree/AUTHORS>.
[root@centos6 bin]#
我真诚地感谢任何帮助来解决这个问题。
提前谢谢。
- 编辑：
预期结果
[root@centos6 bin]# grep -A 2 -B 2 "SampleTextFile.txt" /var/log/messages
Nov 10 00:14:54 centos6 kernel: Kernel logging (proc) stopped.
Nov 10 00:14:54 centos6 rsyslogd: [origin software="rsyslogd" swVersion="5.8.10" x-pid="1513" x-info="http://www.rsyslog.com"] exiting on signal 15.
File SampleTextFile.txt
First Line after original SampleTextFile.txt
Nov 12 18:13:48 centos6 kernel: imklog 5.8.10, log source = /proc/kmsg started.
Nov 12 18:13:48 centos6 rsyslogd: [origin software="rsyslogd" swVersion="5.8.10" x-pid="1519" x-info="http://www.rsyslog.com"] start