每天一个Linux命令 (2) chattr

chattr

chat + tr 聊 行 ??
no
change attributes 改变属性
那么他是改变什么的属性呢???
在Linux里面,只有文件,所以是改变文件的属性。

chattr -RV+/-/=<属性>

-R 递归处理,将指定目录下的所有文件及子目录一并处理。
-v<版本编号> 设置文件或目录版本。
-V 显示指令执行过程。
+<属性> 开启文件或目录的该项属性。
-<属性> 关闭文件或目录的该项属性。
=<属性> 指定文件或目录的该项属性。

1.a:让文件或目录仅供附加用途。
2.b:不更新文件或目录的最后存取时间。
3.c:将文件或目录压缩后存放。
4.d:将文件或目录排除在倾倒操作之外。
5.i:不得任意更动文件或目录。
6.s:保密性删除文件或目录。
7.S:即时更新文件或目录。
8.u:预防意外删除

CHGRP(1) User Commands CHGRP(1)

NAME

   chgrp - change group ownership

SYNOPSIS

   chgrp [OPTION]... GROUP FILE...
   chgrp [OPTION]... --reference=RFILE FILE...

DESCRIPTION

   Change  the  group  of  each  FILE  to GROUP.  With --reference,
   change the group of each FILE to that of RFILE.

   -c, --changes
          like verbose but report only when a change is made

   -f, --silent, --quiet
          suppress most error messages

   -v, --verbose
          output a diagnostic for every file processed

   --dereference

Manual page chgrp(1) line 1 (press h for help or q to quit)...skipping...
CHGRP(1) User Commands CHGRP(1)

NAME

   chgrp - change group ownership

SYNOPSIS

   chgrp [OPTION]... GROUP FILE...
   chgrp [OPTION]... --reference=RFILE FILE...

DESCRIPTION

   Change  the  group  of  each  FILE  to GROUP.  With --reference,
   change the group of each FILE to that of RFILE.

   -c, --changes
          like verbose but report only when a change is made

   -f, --silent, --quiet
          suppress most error messages

   -v, --verbose
          output a diagnostic for every file processed

   --dereference
          affect the referent of each symbolic link  (this  is  the
          default), rather than the symbolic link itself

   -h, --no-dereference
          affect  symbolic  links  instead  of  any referenced file
          (useful only on systems that can change the ownership  of
          a symlink)

   --no-preserve-root
          do not treat '/' specially (the default)

   --preserve-root
          fail to operate recursively on '/'

   --reference=RFILE
          use RFILE's group rather than specifying a GROUP value

   -R, --recursive
          operate on files and directories recursively

   The  following  options modify how a hierarchy is traversed when
   the -R option is also specified.  If more than one is specified,
   only the final one takes effect.

   -H     if a command line argument is a symbolic link to a direc‐
          tory, traverse it

   -L     traverse every symbolic link to a directory encountered

   -P     do not traverse any symbolic links (default)

   --help display this help and exit

   --version
          output version information and exit

EXAMPLES

   chgrp staff /u
          Change the group of /u to "staff".

   chgrp -hR staff /u
          Change the group of /u and subfiles to "staff".

   GNU coreutils  online  help:  <http://www.gnu.org/software/core‐
   utils/> Report chgrp translation bugs to <http://translationpro‐
   ject.org/team/>

AUTHOR

   Written by David MacKenzie and Jim Meyering.

COPYRIGHT

   Copyright © 2013 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.

SEE ALSO

   The full documentation for chgrp is maintained as a Texinfo man‐
   ual.   If  the info and chgrp programs are properly installed at
   your site, the command

          info coreutils 'chgrp invocation'

   should give you access to the complete manual.

GNU coreutils 8.22 April 2018 CHGRP(1)
[root@VM_0_12_centos ~]#
[root@VM_0_12_centos ~]# man chattr
CHATTR(1) General Commands Manual CHATTR(1)

NAME

   chattr - change file attributes on a Linux file system

SYNOPSIS

   chattr [ -RVf ] [ -v version ] [ mode ] files...

DESCRIPTION

   chattr changes the file attributes on a Linux file system.

   The format of a symbolic mode is +-=[aAcCdDeijsStTu].

   The  operator  '+'  causes  the  selected  attributes  to  be added to the existing attributes of the files; '-' causes them to be removed; and '=' causes them to be the only
   attributes that the files have.

   The letters 'aAcCdDeijsStTu' select the new attributes for the files: append only (a), no atime updates (A), compressed (c), no copy on write (C), no  dump  (d),  synchronous
   directory  updates  (D), extent format (e), immutable (i), data journalling (j), secure deletion (s), synchronous updates (S), no tail-merging (t), top of directory hierarchy
   (T), and undeletable (u).

   The following attributes are read-only, and may be listed by lsattr(1) but not modified by chattr: compression error (E), huge file (h), indexed directory  (I),  inline  data
   (N), compression raw access (X), and compressed dirty file (Z).

   Not all flags are supported or utilized by all filesystems; refer to filesystem-specific man pages such as btrfs(5), ext4(5), and xfs(5) for more filesystem-specific details.

OPTIONS

   -R     Recursively change attributes of directories and their contents.

   -V     Be verbose with chattr's output and print the program version.

   -f     Suppress most error messages.

   -v version
          Set the file's version/generation number.

ATTRIBUTES

   A file with the 'a' attribute set can only be open in append mode for writing.  Only the superuser or a process possessing the CAP_LINUX_IMMUTABLE capability can set or clear
   this attribute.

   When a file with the 'A' attribute set is accessed, its atime record is not modified.  This avoids a certain amount of disk I/O for laptop systems.

   A file with the 'c' attribute set is automatically compressed on the disk by the kernel.  A read from this file returns uncompressed data.  A write to  this  file  compresses
   data before storing them on the disk.  Note: please make sure to read the bugs and limitations section at the end of this document.

   A  file  with the 'C' attribute set will not be subject to copy-on-write updates.  This flag is only supported on file systems which perform copy-on-write.  (Note: For btrfs,
   the 'C' flag should be set on new or empty files.  If it is set on a file which already has data blocks, it is undefined when the blocks assigned to the file  will  be  fully
   stable.  If the 'C' flag is set on a directory, it will have no effect on the directory, but new files created in that directory will the No_COW attribute.)

   A file with the 'd' attribute set is not candidate for backup when the dump(8) program is run.

   When a directory with the 'D' attribute set is modified, the changes are written synchronously on the disk; this is equivalent to the 'dirsync' mount option applied to a sub‐
   set of the files.

   The 'e' attribute indicates that the file is using extents for mapping the blocks on disk.  It may not be removed using chattr(1).

   The 'E' attribute is used by the experimental compression patches to indicate that a compressed file has a compression error.  It may not be set  or  reset  using  chattr(1),
   although it can be displayed by lsattr(1).

   The  'h'  attribute  indicates  the file is storing its blocks in units of the filesystem blocksize instead of in units of sectors, and means that the file is (or at one time
   was) larger than 2TB.  It may not be set or reset using chattr(1), although it can be displayed by lsattr(1).

   A file with the 'i' attribute cannot be modified: it cannot be deleted or renamed, no link can be created to this file and no data can be written to the file.  Only the supe‐
   ruser or a process possessing the CAP_LINUX_IMMUTABLE capability can set or clear this attribute.

   The  'I' attribute is used by the htree code to indicate that a directory is being indexed using hashed trees.  It may not be set or reset using chattr(1), although it can be
   displayed by lsattr(1).

   A file with the 'j' attribute has all of its data written to the ext3 or ext4 journal before being written to  the  file  itself,  if  the  filesystem  is  mounted  with  the
   "data=ordered"  or  "data=writeback"  options.   When  the  filesystem is mounted with the "data=journal" option all file data is already journalled and this attribute has no
   effect.  Only the superuser or a process possessing the CAP_SYS_RESOURCE capability can set or clear this attribute.

   A file with the 'N' attribute set indicates that the file has data stored inline, within the inode itself. It may not be set or reset using chattr(1), although it can be dis‐
   played by lsattr(1).

   When a file with the 's' attribute set is deleted, its blocks are zeroed and written back to the disk.  Note: please make sure to read the bugs and limitations section at the
   end of this document.

   When a file with the 'S' attribute set is modified, the changes are written synchronously on the disk; this is equivalent to the 'sync' mount option applied to  a  subset  of
   the files.

   A  file with the 't' attribute will not have a partial block fragment at the end of the file merged with other files (for those filesystems which support tail-merging).  This
   is necessary for applications such as LILO which read the filesystem directly, and which don't understand tail-merged files.  Note: As of  this  writing,  the  ext2  or  ext3
   filesystems do not (yet, except in very experimental patches) support tail-merging.

   A directory with the 'T' attribute will be deemed to be the top of directory hierarchies for the purposes of the Orlov block allocator.  This is a hint to the block allocator
   used by ext3 and ext4 that the subdirectories under this directory are not related, and thus should be spread apart for allocation purposes.   For example it is a  very  good
   idea  to  set  the 'T' attribute on the /home directory, so that /home/john and /home/mary are placed into separate block groups.  For directories where this attribute is not
   set, the Orlov block allocator will try to group subdirectories closer together where possible.

   When a file with the 'u' attribute set is deleted, its contents are saved.  This allows the user to ask for its undeletion.  Note: please make sure to read the bugs and limi‐
   tations section at the end of this document.

   The  'X'  attribute  is used by the experimental compression patches to indicate that the raw contents of a compressed file can be accessed directly.  It currently may not be
   set or reset using chattr(1), although it can be displayed by lsattr(1).

   The 'Z' attribute is used by the experimental compression patches to indicate a compressed file is dirty.  It may not be set or reset using chattr(1), although it can be dis‐
   played by lsattr(1).

AUTHOR

   chattr was written by Remy Card <Remy.Card@linux.org>.  It is currently being maintained by Theodore Ts'o <tytso@alum.mit.edu>.

BUGS AND LIMITATIONS

   The 'c', 's',  and 'u' attributes are not honored by the ext2, ext3, and ext4 filesystems as implemented in the current mainline Linux kernels.

   The 'j' option is only useful if the filesystem is mounted as ext3 or ext4.

   The 'D' option is only useful on Linux kernel 2.5.19 and later.

AVAILABILITY

   chattr is part of the e2fsprogs package and is available from http://e2fsprogs.sourceforge.net.

SEE ALSO

   lsattr(1), btrfs(5), ext4(5), xfs(5).

E2fsprogs version 1.42.9
相关链接:
每天一个Linux命令(1) cat

本文链接:

https://heyzen.club/index.php/Coder/47.html
1 + 9 =
快来做第一个评论的人吧~