【背景】
想要在Linux下面，找之前不知道放到哪里的一个tomcat的文件。
【折腾过程】
1.最后是参考：
linux查找文件命令find – 发芽的石头 – 博客频道 – CSDN.NET
去搜：
root@bogon:openfire# find / -name '*tomcat*'
/usr/local/tomcat1
/usr/local/tomcat1/conf/tomcat-users.xml
/usr/local/tomcat1/lib/tomcat-util.jar
/usr/local/tomcat1/lib/tomcat-i18n-ja.jar
/usr/local/tomcat1/lib/tomcat-coyote.jar
/usr/local/tomcat1/lib/tomcat-i18n-fr.jar
/usr/local/tomcat1/lib/tomcat7-websocket.jar
/usr/local/tomcat1/lib/tomcat-dbcp.jar
/usr/local/tomcat1/lib/tomcat-i18n-es.jar
/usr/local/tomcat1/lib/tomcat-jdbc.jar
/usr/local/tomcat1/lib/tomcat-api.jar
/usr/local/tomcat1/webapps/manager/images/tomcat.gif
/usr/local/tomcat1/webapps/ROOT/tomcat.css
/usr/local/tomcat1/webapps/ROOT/tomcat.gif
/usr/local/tomcat1/webapps/ROOT/tomcat-power.gif
/usr/local/tomcat1/webapps/ROOT/tomcat.svg
/usr/local/tomcat1/webapps/ROOT/tomcat.png
/usr/local/tomcat1/webapps/host-manager/images/tomcat.gif
/usr/local/tomcat1/webapps/docs/images/tomcat.gif
/usr/local/tomcat1/webapps/docs/images/tomcat.svg
/usr/local/tomcat1/webapps/docs/appdev/sample/web/images/tomcat.gif
/usr/local/tomcat1/bin/tomcat-native.tar.gz
/usr/local/tomcat1/bin/tomcat-juli.jar
/usr/sbin/tomcat6
/usr/sbin/dtomcat6
/usr/bin/tomcat6-digest
/usr/bin/tomcat6-tool-wrapper
/usr/share/tomcat6
/usr/share/tomcat6/bin/tomcat-juli.jar
/usr/share/tomcat6/bin/tomcat-juli-6.0.24.jar
/usr/share/selinux/devel/include/services/tomcat.if
/usr/share/selinux/targeted/tomcat.pp.bz2
/usr/share/doc/apache-tomcat-apis-0.1
/usr/share/doc/tomcat6-6.0.24
/usr/share/java/tomcat6
/usr/share/java/tomcat6/tomcat-i18n-fr-6.0.24.jar
/usr/share/java/tomcat6/tomcat-i18n-ja.jar
/usr/share/java/tomcat6/tomcat-juli.jar
/usr/share/java/tomcat6/tomcat-coyote.jar
/usr/share/java/tomcat6/tomcat-i18n-fr.jar
/usr/share/java/tomcat6/tomcat6-jsp-2.1-api-6.0.24.jar
/usr/share/java/tomcat6/tomcat-i18n-ja-6.0.24.jar
/usr/share/java/tomcat6/tomcat6-el-2.1-api-6.0.24.jar
/usr/share/java/tomcat6/tomcat6-servlet-2.5-api-6.0.24.jar
/usr/share/java/tomcat6/tomcat-coyote-6.0.24.jar
/usr/share/java/tomcat6/tomcat-i18n-es.jar
/usr/share/java/tomcat6/extras/tomcat-juli.jar
/usr/share/java/tomcat6/extras/tomcat-juli-adapters.jar
/usr/share/java/tomcat6/tomcat-i18n-es-6.0.24.jar
/usr/share/java/apache-tomcat-apis
/usr/share/java/apache-tomcat-apis/tomcat-jsp2.1-api.jar
/usr/share/java/apache-tomcat-apis/tomcat-servlet2.5-api.jar
/usr/share/java/apache-tomcat-apis/tomcat-jsp2.0-api.jar
/usr/share/java/apache-tomcat-apis/tomcat-servlet2.4-api.jar
/usr/share/java/tomcat6-servlet-2.5-api.jar
/usr/share/java/tomcat6-jsp-2.1-api-6.0.24.jar
/usr/share/java/tomcat6-el-2.1-api-6.0.24.jar
/usr/share/java/tomcat6-servlet-2.5-api-6.0.24.jar
/usr/share/java/tomcat6-el-2.1-api.jar
/usr/share/java/tomcat6-jsp-2.1-api.jar
/var/lib/tomcat6
/var/lib/tomcat6/webapps/manager/images/tomcat.gif
/var/lib/tomcat6/webapps/sample/images/tomcat.gif
/var/lib/tomcat6/webapps/ROOT/tomcat.gif
/var/lib/tomcat6/webapps/ROOT/tomcat-power.gif
/var/lib/tomcat6/webapps/ROOT/tomcat.svg
/var/lib/tomcat6/webapps/host-manager/images/tomcat.gif
/var/lib/yum/yumdb/a/e35f1b8f8c6e2f285fc0214286e0b03beaf5e852-apache-tomcat-apis-0.1-1.el6-noarch
/var/lib/yum/yumdb/t/0c3c81b5aaba908a837902db4cba8076f2e7cc5d-tomcat6-lib-6.0.24-83.el6_6-x86_64
/var/lib/yum/yumdb/t/02426ee47b3a07f259586c51c37c8359f1c7627d-tomcat6-servlet-2.5-api-6.0.24-83.el6_6-x86_64
/var/lib/yum/yumdb/t/b60f2e9f994eb122122cf02114b51164ff7dd4c3-tomcat6-admin-webapps-6.0.24-83.el6_6-x86_64
/var/lib/yum/yumdb/t/f3acc3eab248f6f1009abdc219c1d3bea9a025ec-tomcat6-webapps-6.0.24-83.el6_6-x86_64
/var/lib/yum/yumdb/t/508295a2c951bee066ef29f46f78a02b6c50a11c-tomcat6-el-2.1-api-6.0.24-83.el6_6-x86_64
/var/lib/yum/yumdb/t/bc2836feb5319c5623fe1c243697dba038203642-tomcat6-6.0.24-83.el6_6-x86_64
/var/lib/yum/yumdb/t/9cd8fa43f523ea3019f4e806f1cb75cbd65343df-tomcat6-jsp-2.1-api-6.0.24-83.el6_6-x86_64
/var/run/tomcat6.pid
/var/log/tomcat6
/var/log/tomcat6-initd.log
/var/lock/subsys/tomcat6
/var/cache/tomcat6
/etc/tomcat6
/etc/tomcat6/tomcat-users.xml
/etc/tomcat6/tomcat6.conf
/etc/selinux/targeted/modules/active/modules/tomcat.pp
/etc/rc.d/init.d/tomcat6
/etc/rc.d/rc4.d/K20tomcat6
/etc/rc.d/rc2.d/K20tomcat6
/etc/rc.d/rc1.d/K20tomcat6
/etc/rc.d/rc6.d/K20tomcat6
/etc/rc.d/rc3.d/K20tomcat6
/etc/rc.d/rc5.d/K20tomcat6
/etc/rc.d/rc0.d/K20tomcat6
/etc/logrotate.d/tomcat6
/etc/sysconfig/tomcat6
/tmp/hsperfdata_tomcat
root@bogon:openfire#
2.后来又去试试其他的：
crifan@crifan:~$ find / -name '*dovecot.pem*'
find: ‘/sys/kernel/debug’: Permission denied
find: ‘/home/vmail’: Permission denied
/home/crifan/mail_server/dovecot/certs/dovecot.pem
/home/crifan/mail_server/dovecot/private/dovecot.pem
find: ‘/tmp/systemd-private-rCKJi3’: Permission denied
find: ‘/tmp/systemd-private-Fuif7J’: Permission denied
find: ‘/tmp/systemd-private-FhTYag’: Permission denied
find: ‘/run/httpd’: Permission denied
find: ‘/run/dovecot/token-login’: Permission denied
find: ‘/run/dovecot/login’: Permission denied
find: ‘/run/systemd/ask-password-block’: Permission denied
find: ‘/run/systemd/inaccessible’: Permission denied
find: ‘/usr/share/polkit-1/rules.d’: Permission denied
find: ‘/usr/lib/firewalld/icmptypes’: Permission denied
find: ‘/usr/lib/firewalld/services’: Permission denied
find: ‘/usr/lib/firewalld/zones’: Permission denied
find: ‘/usr/libexec/initscripts/legacy-actions/auditd’: Permission denied
find: ‘/var/cache/httpd/proxy’: Permission denied
find: ‘/var/db/sudo’: Permission denied
find: ‘/var/tmp/systemd-private-sl8Rw5’: Permission denied
find: ‘/var/tmp/systemd-private-4xjKJH’: Permission denied
find: ‘/var/tmp/systemd-private-ckkDHo’: Permission denied
find: ‘/var/spool/postfix/flush’: Permission denied
find: ‘/var/spool/postfix/corrupt’: Permission denied
find: ‘/var/spool/postfix/incoming’: Permission denied
find: ‘/var/spool/postfix/hold’: Permission denied
find: ‘/var/spool/postfix/public’: Permission denied
find: ‘/var/spool/postfix/active’: Permission denied
find: ‘/var/spool/postfix/deferred’: Permission denied
find: ‘/var/spool/postfix/bounce’: Permission denied
find: ‘/var/spool/postfix/saved’: Permission denied
find: ‘/var/spool/postfix/trace’: Permission denied
find: ‘/var/spool/postfix/defer’: Permission denied
find: ‘/var/spool/postfix/private’: Permission denied
find: ‘/var/spool/postfix/maildrop’: Permission denied
find: ‘/var/lib/authconfig/last’: Permission denied
find: ‘/var/lib/polkit-1/localauthority’: Permission denied
find: ‘/var/lib/php/session’: Permission denied
find: ‘/var/lib/mysql/crifan_wiki’: Permission denied
find: ‘/var/lib/mysql/mail’: Permission denied
find: ‘/var/lib/dovecot’: Permission denied
find: ‘/var/lib/postfix’: Permission denied
find: ‘/var/lib/tpm’: Permission denied
find: ‘/var/lib/yum/history/2014-07-07/32’: Permission denied
find: ‘/var/lib/yum/history/2014-07-07/36’: Permission denied
find: ‘/var/lib/yum/history/2014-07-07/35’: Permission denied
find: ‘/var/lib/yum/history/2014-07-07/31’: Permission denied
find: ‘/var/lib/yum/history/2014-07-07/37’: Permission denied
find: ‘/var/lib/yum/history/2014-07-07/34’: Permission denied
find: ‘/var/lib/yum/history/2014-07-07/33’: Permission denied
^C
crifan@crifan:~$ sudo find / -name '*dovecot.pem*'
[sudo] password for crifan:
/home/crifan/mail_server/dovecot/certs/dovecot.pem
/home/crifan/mail_server/dovecot/private/dovecot.pem
/etc/pki/dovecot/certs/dovecot.pem
/etc/pki/dovecot/private/dovecot.pem
如图：
其中的^C是发现很多文件没有权限，所以Ctrl+C去终止了。
然后加上sudo，就有权限去搜索了。
【总结】
想要在Linux下面查找文件，尤其是只知道部分文件名，关键字，则可以去用：
find 路径 -name ‘*要搜的关键字*’
比如：
find / -name '*tomcat*'
即可。
如果要搜的路径或文件涉及到没有权限，即出现Permission denied，则可以加上前缀sudo，比如：
sudo find / -name '*dovecot.pem*'
即可。