Linux的chattr与lsattr命令介绍

Posted 2020-09-09

Linux的chattr与lsattr命令介绍

命令lsattr是用来查看文件、目录属性的，命令chattr是用来对其做更改的。与chmod这个命令相比，chmod只是改变文件的读写、执行权限，更底层的属性控制是由chattr来改变的。

chattr命令语法：

chattr [+-=][Asaci][文件或者目录名]

注：+表示增加，-表示减少，=表示设定。

• A：增加该属性后，表示文件或者目录的atime将不可修改。

• s：增加该属性后，会将数据同步写入磁盘中。

• a：增加该属性后，表示只能追加不能删除，非root用户不能设定该属性。

• c：增加该属性后，表示自动压缩该文件，读取时会自动解压。

• i：增加该属性后，表示文件不能被删除、重命名、设定链接、写入以及新增数据。

注：实际工作中运用的最多的就是两个参数：i和a

举例说明：lsattr

[[email protected] ~]# lsattr

-------------e- ./wu.txt

-------------e- ./install.log.syslog

-------------e- ./anaconda-ks.cfg

-------------e- ./install.log

注：e表示ext4或ext3所持人的权限。

[[email protected] ~]# chattr +a wu.txt

[[email protected] ~]# lsattr

-----a-------e- ./wu.txt

-------------e- ./install.log.syslog

-------------e- ./anaconda-ks.cfg

-------------e- ./install.log

[[email protected] ~]# echo ‘111111‘ >> wu.txt

[[email protected] ~]# cat wu.txt

111111

[[email protected] ~]# rm -rf wu.txt

rm: cannot remove `wu.txt‘: Operation not permitted

[[email protected] ~]# echo ‘2222‘ > wu.txt

-bash: wu.txt: Operation not permitted

上述中：wu.txt文件增加a权限后，只可以追加，不能重定向及删除！

[[email protected] ~]# mkdir shiyan

[[email protected] ~]# lsattr

-----a-------e- ./wu.txt

-------------e- ./install.log.syslog

-------------e- ./anaconda-ks.cfg

-------------e- ./install.log

-------------e- ./shiyan

[[email protected] ~]# chattr +a shiyan

[[email protected] ~]# lsattr

-----a-------e- ./wu.txt

-------------e- ./install.log.syslog

-------------e- ./anaconda-ks.cfg

-------------e- ./install.log

-----a-------e- ./shiyan

[[email protected] ~]# touch shiyan/test1

[[email protected] ~]# cd shiyan

[[email protected] shiyan]# lsattr

-------------e- ./test1

[[email protected] shiyan]# rm -rf test1

rm: cannot remove `test1‘: Operation not permitted

上述中：shiyan目录增加a权限后，只可以在里面创建文件，而不能删除文件！

[[email protected] ~]# chattr -a shiyan

[[email protected] ~]# chattr -a wu.txt

[[email protected] ~]# ls

anaconda-ks.cfg  install.log  install.log.syslog  shiyan  wu.txt

[[email protected] ~]# lsattr

-------------e- ./wu.txt

-------------e- ./install.log.syslog

-------------e- ./anaconda-ks.cfg

-------------e- ./install.log

-------------e- ./shiyan

[[email protected] ~]# chattr +i wu.txt

[[email protected] ~]# lsattr wu.txt

----i--------e- wu.txt

[[email protected] ~]# echo ‘nihao‘ >> wu.txt

-bash: wu.txt: Permission denied

[[email protected] ~]# echo ‘nihao‘ > wu.txt

-bash: wu.txt: Permission denied

[[email protected] ~]# rm -rf wu.txt

rm: cannot remove `wu.txt‘: Operation not permitted

上述中：给wu.txt增加i权限之后，文件即使在root账户下也不能进行追加、重定向、删除等操作！

[[email protected] ~]# lsattr

----i--------e- ./wu.txt

-------------e- ./install.log.syslog

-------------e- ./anaconda-ks.cfg

-------------e- ./install.log

----i--------e- ./shiyan

[[email protected] ~]# touch shiyan/test2

touch: cannot touch `shiyan/test2‘: Permission denied

[[email protected] ~]# rm -rf shiyan

rm: cannot remove `shiyan/test1‘: Permission denied

上述中：给shiyan目录增加i权限之后，即使在root账户下也不能在shiyan目录下创建文件test1及删除shiyan这个目录等操作！

[[email protected] ~]# chattr -i shiyan

[[email protected] ~]# chattr -i wu.txt

[[email protected] ~]# lsattr

-------------e- ./wu.txt

-------------e- ./install.log.syslog

-------------e- ./anaconda-ks.cfg

-------------e- ./install.log

-------------e- ./shiyan

[[email protected] ~]# rm -rf shiyan;rm -rf wu.txt

[[email protected] ~]# lsattr

-------------e- ./install.log.syslog

-------------e- ./anaconda-ks.cfg

-------------e- ./install.log

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