记录linux下最近碰到的错误

1. 由时间引起的：
编译安装Sys-Statistics-Linux

perl Makefile.PL
make
make install

每次make 都会报错，我一直在考虑各种包的依赖关系，终于让发现了不少包需要装。

yum install perl-Time-HiRes
yum install perl-ExtUtils-CBuilder perl-ExtUtils-MakeMaker
yum install perl-Test-Simple perl-Test-Harness perl-Test-Pod-Coverage perl-Test-Pod

但是其实真正的问题出在哪里呢？时间是错误的,更新完时间后， Sys-Statistics-Linux安装成功，nrpe也安装成功了。

date
Mon Jan 5 19:38:08 EST 1970
ntpdate 192.168.*.*         //ntpdate update time

2. 链接：
用一个账户kobe建立一个1.txt,然后用root来分别对这个文件做软链接和硬链接。
A.可以看到硬链接保持了文件oid和gid, 而我用root 建立的软连接 3.txt 则uid和gid 都是root.

4 -rw-rw-r--. 2 kobe kobe   14 Oct 23 09:30 1.txt
4 -rw-rw-r--. 2 kobe kobe   14 Oct 23 09:30 2.txt
0 lrwxrwxrwx. 1 root root    5 Oct 23 09:33 3.txt -> 1.txt

B. 可以看到硬链接和原始文件的Inode是相同的，而软连接则不是。

[root@c653f1u25 tmp]# stat 1.txt
  File: ‘1.txt’
  Size: 14            Blocks: 8          IO Block: 4096   regular file
Device: fd00h/64768d    Inode: 5846        Links: 2
Access: (0664/-rw-rw-r--) Uid: ( 1000/    kobe) Gid: ( 1000/    kobe)
Context: unconfined_u:object_r:user_tmp_t:s0
Access: 2015-10-23 09:32:04.204412959 -0400
Modify: 2015-10-23 09:30:17.986761312 -0400
Change: 2015-10-23 09:31:55.253358045 -0400
 Birth: -
[root@c653f1u25 tmp]# stat 2.txt
  File: ‘2.txt’
  Size: 14            Blocks: 8          IO Block: 4096   regular file
Device: fd00h/64768d    Inode: 5846        Links: 2
Access: (0664/-rw-rw-r--) Uid: ( 1000/    kobe) Gid: ( 1000/    kobe)
Context: unconfined_u:object_r:user_tmp_t:s0
Access: 2015-10-23 09:32:04.204412959 -0400
Modify: 2015-10-23 09:30:17.986761312 -0400
Change: 2015-10-23 09:31:55.253358045 -0400
 Birth: -
[root@c653f1u25 tmp]# stat 3.txt
  File: ‘3.txt’ -> ‘1.txt’
  Size: 5             Blocks: 0          IO Block: 4096   symbolic link
Device: fd00h/64768d    Inode: 5848        Links: 1
Access: (0777/lrwxrwxrwx) Uid: ( 0/    root) Gid: ( 0/    root)
Context: unconfined_u:object_r:user_tmp_t:s0
Access: 2015-10-26 02:35:49.017516496 -0400
Modify: 2015-10-23 09:33:25.094909175 -0400
Change: 2015-10-23 09:33:25.094909175 -0400
 Birth: -

估计这些信息都是来自于这个结构体：

struct stat {
               dev_t     st_dev; /* ID of device containing file */
               ino_t     st_ino; /* inode number */
               mode_t    st_mode; /* protection */
               nlink_t   st_nlink; /* number of hard links */
               uid_t     st_uid; /* user ID of owner */
               gid_t     st_gid; /* group ID of owner */
               dev_t     st_rdev; /* device ID (if special file) */
               off_t     st_size; /* total size, in bytes */
               blksize_t st_blksize; /* blocksize for file system I/O */
               blkcnt_t  st_blocks; /* number of 512B blocks allocated */
               time_t    st_atime; /* time of last access */
               time_t    st_mtime; /* time of last modification */
               time_t    st_ctime; /* time of last status change */
           }