How to modify squashfs image

/**********************************************************************
 *                  How to modify squashfs image
 * 说明：
 *     本文如何使用squashfs-tools对squashfs image进行解压及合成。
 *
 *                                    2016-4-27 深圳 南山平山村 曾剑锋
 *********************************************************************/

参考文档：
    How to modify squashfs image
        https://blog.sleeplessbeastie.eu/2012/05/27/how-to-modify-squashfs-image/

You cannot modify squashfs image directly but you can uncompress it, apply changes and compress it again.
你不能直接修改squashfs镜像，当时你可以解压他，然后修改文件，最后在压缩他。

Create temporary directory and enter it:
创建暂存文件夹，并进入：
    $ mkdir squashfs-temp
    $ cd squashfs-temp

To uncompress squashfs image (into squashfs-root directory) use unsquashfs command:
解压squashfs镜像(进入squashfs-root文件夹)使用unsquashfs命令：
    $ unsquashfs /live/image/livefs.squashfs
    Parallel unsquashfs: Using  processors
     inodes ( blocks) to write

    [===========================================================-] / %
    created  files
    created  directories
    created  symlinks
    created  devices
    created  fifos

After applying required changes you can compress it using mksquashfs command:
修改完你的需求之后，重新压缩并制作squashfs镜像：
    $ mksquashfs squashfs-root/ livefs.squashfs -noappend -always-use-fragments
    Parallel mksquashfs: Using  processors
    Creating 4.0 filesystem on livefs.squashfs, block size .
    [===========================================================|] / %
    Exportable Squashfs 4.0 filesystem, gzip compressed, data block size
          compressed data, compressed metadata, compressed fragments, compressed xattrs
          duplicates are removed
    Filesystem size 1191282.88 Kbytes (1163.36 Mbytes)
          46.01% of uncompressed filesystem size (2589278.95 Kbytes)
    Inode table size  bytes (883.83 Kbytes)
          29.51% of uncompressed inode table size ( bytes)
    Directory table size  bytes (895.63 Kbytes)
          44.02% of uncompressed directory table size ( bytes)
    Number of duplicate files found
    Number of inodes
    Number of files
    Number of fragments
    Number of symbolic links
    Number of device nodes
    Number of fifo nodes
    Number of socket nodes
    Number of directories
    Number of ids (unique uids + gids)
    Number of uids
          root ()
          daemon ()
          milosz ()
          kdm ()
          libuuid ()
          man ()
    Number of gids
          root ()
          daemon ()
          fuse ()
          shadow ()
          milosz ()
          vboxsf ()
          tty ()
          crontab ()
          mail ()
          mlocate ()
          ssh ()
          messagebus ()
          nogroup ()
          utmp ()
          utempter ()
          staff ()
          libuuid ()