Linux查找文件内容的常用命令方法。
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从文件内容查找匹配指定字符串的行：
$ grep "被查找的字符串" 文件名
例子：在当前目录里第一级文件夹中寻找包含指定字符串的.in文件
grep "thermcontact" */*.in
从文件内容查找与正则表达式匹配的行：
$ grep –e “正则表达式” 文件名
查找时不区分大小写：
$ grep –i "被查找的字符串" 文件名
查找匹配的行数：
$ grep -c "被查找的字符串" 文件名
从文件内容查找不匹配指定字符串的行：
$ grep –v "被查找的字符串" 文件名
学习更多linux知识《Linux就该这么学》，从根目录开始查找所有扩展名为.log的文本文件，并找出包含”ERROR”的行
find / -type f -name "*.log" | xargs grep "ERROR"
例子：从当前目录开始查找所有扩展名为.in的文本文件，并找出包含”thermcontact”的行
find . -name "*.in" | xargs grep "thermcontact"
搜索、查找文件当中的内容，一般最常用的是grep命令，另外还有egrep, vi命令也能搜索文件里面内容
1：搜索某个文件里面是否包含字符串，使用grep "search content" filename1， 例如
$ grep ORA alert_gsp.log
$ grep "ORA" alert_gsp.log
例如我们需要搜索、查找utlspadv.sql文件中包含ORA的字符内容
[oracle@DB-Server admin]$ grep "ORA" utlspadv.sql
-- ORA-XXXXX: Monitoring already started. If for example you want
-- ORA-20111:
-- ORA-20112:
-- ORA-20113: 'no active monitoring job found'
-- ORA-20113: 'no active monitoring job found'
-- 0 |PS =DBS2.REGRESS.RDBMS.DEV.US.ORACLE.COM 0 0 2 99.3% 0% 0.7% ""
-- |PR DBS1.REGRESS.RDBMS.DEV.US.ORACLE.COM= 100% 0% 0% "" |PR ...
-- =DBS2.REGRESS.RDBMS.DEV.US.ORACLE.COM 92 7 99.3% 0% 0.7% "" |PR ...
-- |C CAPTURE_USER1=DBS2.REGRESS.RDBMS.DEV.US.ORACLE.COM 2 0 0 0.E+00
-- |C CAPTURE_USER1=DBS2.REGRESS.RDBMS.DEV.US.ORACLE.COM
-- ORA-20111:
-- ORA-20112:
-- ORA-20100:
-- ORA-20113: 'no active monitoring job found'
-- ORA-20113: 'no active monitoring job found'
[oracle@DB-Server admin]$
如上所示，这个是一个模糊匹配，其实我是想要查看ORA这类错误，那么我要过滤掉哪一些没有用的，搜索的内容修改一下即可（当然也可以使用特殊参数，后面有讲述），如下所示。
[oracle@DB-Server admin]$ grep "ORA-" utlspadv.sql
-- ORA-XXXXX: Monitoring already started. If for example you want
-- ORA-20111:
-- ORA-20112:
-- ORA-20113: 'no active monitoring job found'
-- ORA-20113: 'no active monitoring job found'
-- ORA-20111:
-- ORA-20112:
-- ORA-20100:
-- ORA-20113: 'no active monitoring job found'
-- ORA-20113: 'no active monitoring job found'
[oracle@DB-Server admin]$
2: 如果你想搜索多个文件是否包含某个字符串,可以使用下面方式
grep "search content" filename1 filename2.... filenamen
grep "search content" *.sql
例如我想查看当前目录下,哪些sql脚本包含视图v$temp_space_header（注意：搜索的内容如果包含特殊字符时，必须进行转义处理，如下所示）
[oracle@DB-Server admin]$ grep "v\$temp_space_header" *.sql
catspacd.sql:drop public synonym v$temp_space_header;
catspacd.sql:drop public synonym gv$temp_space_header;
catspace.sql:create or replace view v_$temp_space_header as select * from v$temp_space_header;
catspace.sql:create or replace public synonym v$temp_space_header for v_$temp_space_header;
catspace.sql:create or replace view gv_$temp_space_header as select * from gv$temp_space_header;
catspace.sql:create or replace public synonym gv$temp_space_header
catspace.sql: FROM gv$temp_space_header
[oracle@DB-Server admin]$
3：如果需要显示搜索文本在文件中的行数，可以使用参数-n
[oracle@DB-Server admin]$ grep -n "v\$temp_space_header" *.sql
catspacd.sql:68:drop public synonym v$temp_space_header;
catspacd.sql:71:drop public synonym gv$temp_space_header;
catspace.sql:1952:create or replace view v_$temp_space_header as select * from v$temp_space_header;
catspace.sql:1953:create or replace public synonym v$temp_space_header for v_$temp_space_header;
catspace.sql:1956:create or replace view gv_$temp_space_header as select * from gv$temp_space_header;
catspace.sql:1957:create or replace public synonym gv$temp_space_header
catspace.sql:2357: FROM gv$temp_space_header
[oracle@DB-Server admin]$
4: 如果搜索时需要忽略大小写问题，可以使用参数-i
[oracle@DB-Server admin]$ grep "V\$TEMP_SPACE_HEADER" *.sql
[oracle@DB-Server admin]$ grep -i "V\$TEMP_SPACE_HEADER" *.sql
catspacd.sql:drop public synonym v$temp_space_header;
catspacd.sql:drop public synonym gv$temp_space_header;
catspace.sql:create or replace view v_$temp_space_header as select * from v$temp_space_header;
catspace.sql:create or replace public synonym v$temp_space_header for v_$temp_space_header;
catspace.sql:create or replace view gv_$temp_space_header as select * from gv$temp_space_header;
catspace.sql:create or replace public synonym gv$temp_space_header
catspace.sql: FROM gv$temp_space_header
[oracle@DB-Server admin]$
另外，例如检查安装的MySQL组件
[root@DB-Server init.d]# rpm -qa | grep -i mysql
MySQL-devel-5.6.23-1.linux_glibc2.5
MySQL-client-5.6.23-1.linux_glibc2.5
MySQL-server-5.6.23-1.linux_glibc2.5
5：从文件内容查找不匹配指定字符串的行：
$ grep –v "被查找的字符串" 文件名
例如查找某些进程时，我们不想显示包含命令grep ora_mmon的进程，如下所示
[oracle@DB-Server admin]$ ps -ef | grep ora_mmon
oracle 16675 16220 0 00:09 pts/1 00:00:00 grep ora_mmon
oracle 21412 1 0 Aug22 ? 00:00:07 ora_mmon_gsp
[oracle@DB-Server admin]$ ps -ef | grep ora_mmon | grep -v grep
oracle 21412 1 0 Aug22 ? 00:00:07 ora_mmon_gsp
[oracle@DB-Server admin]$
6：搜索、查找匹配的行数：
$ grep -c "被查找的字符串" 文件名
[oracle@DB-Server admin]$
[oracle@DB-Server admin]$ grep "v\$temp_space_header" *.sql
catspacd.sql:drop public synonym v$temp_space_header;
catspacd.sql:drop public synonym gv$temp_space_header;
catspace.sql:create or replace view v_$temp_space_header as select * from v$temp_space_header;
catspace.sql:create or replace public synonym v$temp_space_header for v_$temp_space_header;
catspace.sql:create or replace view gv_$temp_space_header as select * from gv$temp_space_header;
catspace.sql:create or replace public synonym gv$temp_space_header
catspace.sql: FROM gv$temp_space_header
[oracle@DB-Server admin]$ grep -c "v\$temp_space_header" catspacd.sql
2
[oracle@DB-Server admin]$ grep -c "v\$temp_space_header" catspace.sql
5
[oracle@DB-Server admin]$
7：有些场景，我们并不知道文件类型、或那些文件包含有我们需要搜索的字符串，那么可以递归搜索某个目录以及子目录下的所有文件
[oracle@DB-Server ~]$ grep -r "v\$temp_space_header" /u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/
/u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/catspace.sql:create or replace view v_$temp_space_header as select * from v$temp_space_header;
/u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/catspace.sql:create or replace public synonym v$temp_space_header for v_$temp_space_header;
/u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/catspace.sql:create or replace view gv_$temp_space_header as select * from gv$temp_space_header;
/u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/catspace.sql:create or replace public synonym gv$temp_space_header
/u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/catspace.sql: FROM gv$temp_space_header
/u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/catspacd.sql:drop public synonym v$temp_space_header;
/u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/catspacd.sql:drop public synonym gv$temp_space_header;
[oracle@DB-Server ~]$
8：如果我们只想获取那些文件包含搜索的内容，那么可以使用下命令
[oracle@DB-Server ~]$ grep -H -r "v\$temp_space_header" /u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/ | cut -d: -f1
/u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/catspace.sql
/u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/catspace.sql
/u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/catspace.sql
/u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/catspace.sql
/u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/catspace.sql
/u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/catspacd.sql
/u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/catspacd.sql
[oracle@DB-Server ~]$ grep -H -r "v\$temp_space_header" /u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/ | cut -d: -f1 | uniq
/u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/catspace.sql
/u01/app/oracle/product/11.1.0/dbhome_1/rdbms/admin/catspacd.sql
[oracle@DB-Server ~]$
9：如果只想获取和整个搜索字符匹配的内容，那么可以使用参数w
你可以对比一下两者的区别
[oracle@DB-Server admin]$ grep -w "ORA" utlspadv.sql
-- ORA-XXXXX: Monitoring already started. If for example you want
-- ORA-20111:
-- ORA-20112:
-- ORA-20113: 'no active monitoring job found'
-- ORA-20113: 'no active monitoring job found'
-- ORA-20111:
-- ORA-20112:
-- ORA-20100:
-- ORA-20113: 'no active monitoring job found'
-- ORA-20113: 'no active monitoring job found'
[oracle@DB-Server admin]$ grep "ORA" utlspadv.sql
-- ORA-XXXXX: Monitoring already started. If for example you want
-- ORA-20111:
-- ORA-20112:
-- ORA-20113: 'no active monitoring job found'
-- ORA-20113: 'no active monitoring job found'
-- 0 |PS =DBS2.REGRESS.RDBMS.DEV.US.ORACLE.COM 0 0 2 99.3% 0% 0.7% ""
-- |PR DBS1.REGRESS.RDBMS.DEV.US.ORACLE.COM= 100% 0% 0% "" |PR ...
-- =DBS2.REGRESS.RDBMS.DEV.US.ORACLE.COM 92 7 99.3% 0% 0.7% "" |PR ...
-- |C CAPTURE_USER1=DBS2.REGRESS.RDBMS.DEV.US.ORACLE.COM 2 0 0 0.E+00
-- |C CAPTURE_USER1=DBS2.REGRESS.RDBMS.DEV.US.ORACLE.COM
-- ORA-20111:
-- ORA-20112:
-- ORA-20100:
-- ORA-20113: 'no active monitoring job found'
-- ORA-20113: 'no active monitoring job found'
[oracle@DB-Server admin]$
10: grep命令结合find命令搜索
[oracle@DB-Server admin]$ find . -name '*.sql' -exec grep -i 'v\$temp_space_header' {} \; -print
create or replace view v_$temp_space_header as select * from v$temp_space_header;
create or replace public synonym v$temp_space_header for v_$temp_space_header;
create or replace view gv_$temp_space_header as select * from gv$temp_space_header;
create or replace public synonym gv$temp_space_header
FROM gv$temp_space_header
./catspace.sql
drop public synonym v$temp_space_header;
drop public synonym gv$temp_space_header;
./catspacd.sql
[oracle@DB-Server admin]$
11: egrep -w -R 'word1|word2' ~/klbtmp
12: vi命令其实也能搜索文件里面的内容，只不过没有grep命令功能那么方便、强大。
Linux下查看文件内容的命令
查看文件内容的命令：
cat 由第一行开始显示内容，并将所有内容输出
tac 从最后一行倒序显示内容，并将所有内容输出
more根据窗口大小，一页一页的现实文件内容
less 和more类似，但其优点可以往前翻页，而且进行可以搜索字符
head 只显示头几行
tail 只显示最后几行
nl 类似于cat -n，显示时输出行号 《Linux就该这么学》 一起学习linux
tailf 类似于tail -f
linux系统查看文件内容的命令包括但不仅限于cat、tac、more、less、head、tail、nl、tailf,tail –f,
