|||
高级文献管理不会修改原文件
输出存对象> , 追加>>
[root@localhost ~]# dd if=/dev/zero of=/root/guo bs=1 count=1M
1048576+0records in
1048576+0records out
1048576bytes (1.0 MB) copied, 2.72509 s, 385 kB/s
[root@localhost ~]# diff /etc/passwd /pub/ps
[root@localhost ~]# cut -d: -f 1 /etc/passwd |head -n 5
root
bin
daemon
adm
lp
[root@localhost ~]# echo $PATH(root用户和普通用户的path不一样)
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin
[root@localhost~]# su - guo
[guo@localhost ~]$ echo $PATH
/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/guo/bin
[root@localhost~]# find /etc -atime 3
[root@localhost~]# find /etc -type f -size 2M(f表示普通文件,大小2M)
/etc/gconf/gconf.xml.defaults/%gconf-tree.xml
文件系统结构和磁盘的管理
扩展名: linux系统中没有扩展名的概念(.exe .mp4)
怎么样辨别一个文件类型??file命令
[root@localhost ~]# file /etc/passwd
/etc/passwd:ASCII text
[root@localhost ~]# file /bin/ls
/bin/ls:ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked(uses shared libs), for GNU/Linux 2.6.18, stripped
Linux没有记录文件的创建时间:(不是windows系统)stat命令
[root@localhost ~]# stat aaa.txt
File: `aaa.txt'
Size: 1048576 Blocks: 2048 IO Block: 4096 regular file
Device:802h/2050d Inode: 393308 Links: 1
Access:(0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access:2015-07-31 00:53:22.361009971 -0700(访问时间)
Modify:2015-07-31 00:50:20.203009173 -0700
Change:2015-07-31 00:50:20.203009173 -0700(对文件权限修改会影响其变化)
修改系统时间:
[root@localhost~]# date -s 20140404
FriApr 4 00:00:00 PDT 2014
[root@localhost~]# date
FriApr 4 00:00:13 PDT 2014
查看系统版本
[root@localhost ~]# cat /etc/issue
CentOSrelease 6.5 (Final)
Kernelr on an m
文件系统: ext2, ext3, ext4 (mount命令)
[root@localhost ~]# mount
/dev/sda2on / type ext4 (rw)
procon /proc type proc (rw)
sysfson /sys type sysfs (rw)
devptson /dev/pts type devpts (rw,gid=5,mode=620)
tmpfson /dev/shm type tmpfs(rw,rootcontext="system_u:object_r:tmpfs_t:s0")
/dev/sda1on /boot type ext4 (rw)
noneon /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
vmware-vmblockon /var/run/vmblock-fuse type fuse.vmware-vmblock(rw,nosuid,nodev,default_permissions,allow_other)
ext4=inode(inode节点)+block(真正存放数据的地方)(什么意思?)
查看文件的inode节点:
[root@localhostpub]# ls -i ps
524299ps(524299是inode号)
根据inode号删除一个文件
[root@localhostpub]# ls
aa aming guo lei nianchi passwd ps
[root@localhostpub]# ls -i ps
524299ps
[root@localhostpub]# man find
[root@localhostpub]# find / -inum 524299
^C
[root@localhostpub]# find /pub -inum 524299
/pub/ps
[root@localhostpub]# find / -inum 524299
^C
[root@localhostpub]# find /pub -inum 524299
/pub/ps
[root@localhostpub]# ls -i /etc/passwd
263571/etc/passwd
[root@localhostpub]# find / -inum 263571
^C
[root@localhostpub]# find /pub -inum 524299 -exec ls -l {} ;
-rw-r--r--.1 root root 1469 Jul 31 01:13 /pub/ps
[root@localhost pub]# find /pub -inum 524299 -exec ls -l {} ;
-rw-r--r--.1 root root 1469 Jul 31 01:13 /pub/ps
[root@localhost pub]# find /pub -inum 524299 -exec rm -rf {} ;(根据inode删除)
注:乱码文件的inode节点也可以查找
[root@localhostpub]# ls
aa aming guo lei nianchi passwd
符号链接:硬链接和软链接
[root@localhostpub]# touch aaa.txt
[root@localhostpub]# ls
aa aaa.txt aming guo lei nianchi passwd
[root@localhostpub]# vim aaa.txt
[root@localhostpub]# cat aaa.txt
ddddddd
/etc/passwd
Ilove linux
[root@localhost pub]# ln aaa.txt bbb.txt(链接)
[root@localhostpub]# cat bbb.txt
ddddddd
/etc/passwd
Ilove linux
[root@localhost pub]# vim aaa.txt (修改了原文件,加一行aaaaaa)
[root@localhost pub]# cat bbb.txt (一个文件链接成另一个文件的时候,inode节点一样)
ddddddd
/etc/passwd
Ilove linux
aaaaaaa
[root@localhostpub]# ls -li
total24
524295-rw-r--r--. 1 root root 0 Jul 30 20:38aa
524301 -rw-r--r--.2 root root 42 Aug 4 17:57 aaa.txt(inode节点是524301)
524292drwxr-xr-x. 2 root root 4096 Jul 30 20:27 aming
524301 -rw-r--r--.2 root root 42 Aug 4 17:57 bbb.txt(inode节点是524301,同上)
524296drwxrwsr-x. 2 guo root 4096 Jul 30 20:44guo
524298-rw-rw-r--. 1 guo root 0 Jul 30 20:46 lei
524294drwxr-sr-x. 2 root root 4096 Jul 30 20:37 nianchi
524297-rw-r--r--. 1 guo root 1469 Jul 30 20:44passwd
问题:如果我按照节点删除文件,是不是两个文件同时删除了?
软连接:(会创建新的inode节点)
[root@localhost pub]# ln -s aaa.txt ccc.txt
[root@localhostpub]# ls -li
total24
524295-rw-r--r--. 1 root root 0 Jul 30 20:38aa
524301 -rw-r--r--. 2 root root 42 Aug 4 17:57 aaa.txt
524292drwxr-xr-x. 2 root root 4096 Jul 30 20:27 aming
524301-rw-r--r--. 2 root root 42 Aug 4 17:57 bbb.txt
524299 lrwxrwxrwx. 1 root root 7 Aug 4 18:02 ccc.txt ->aaa.txt
524296drwxrwsr-x. 2 guo root 4096 Jul 30 20:44guo
524298-rw-rw-r--. 1 guo root 0 Jul 30 20:46 lei
524294drwxr-sr-x. 2 root root 4096 Jul 30 20:37 nianchi
524297-rw-r--r--. 1 guo root 1469 Jul 30 20:44passwd
[root@localhostpub]# cat ccc.txt
ddddddd
/etc/passwd
Ilove linux
aaaaaaaa
[root@localhostpub]# vim aaa.txt(复制aaaaaa行)
[root@localhostpub]# cat aaa.txt
ddddddd
/etc/passwd
Ilove linux
aaaaaaaa
aaaaaaaa
[root@localhostpub]# cat bbb.txt
ddddddd
/etc/passwd
Ilove linux
aaaaaaaa
aaaaaaaa
[root@localhost pub]# cat ccc.txt(软链接也复制了aaaaaaa行)
ddddddd
/etc/passwd
Ilove linux
aaaaaaaa
aaaaaaaa
[root@localhost pub]# rm -rf aaa.txt(删除原文件,不会删除硬链接文件,但是会删除软链接文件)
[root@localhostpub]# cat bbb.txt
ddddddd
/etc/passwd
Ilove linux
aaaaaaaa
aaaaaaaa
[root@localhostpub]# cat ccc.txt
cat:ccc.txt: No such file or directory
不允许将硬链接作用于目录,而软链接即可以作用于文件,又可以作用于目录。
[root@localhost pub]# ln aming aminghard
ln: `aming': hard link not allowed for directory
[root@localhostpub]# ln -s aming aminghard
[root@localhostpub]# ll
total20
-rw-r--r--.1 root root 0 Jul 30 20:38 aa
drwxr-xr-x.2 root root 4096 Jul 30 20:27 aming
lrwxrwxrwx. 1 root root 5Aug 4 18:12 aminghard -> aming
-rw-r--r--.1 root root 51 Aug 4 18:04 bbb.txt
lrwxrwxrwx.1 root root 7 Aug 4 18:02 ccc.txt -> aaa.txt
drwxrwsr-x.2 guo root 4096 Jul 30 20:44 guo
-rw-rw-r--.1 guo root 0 Jul 30 20:46 lei
drwxr-sr-x.2 root root 4096 Jul 30 20:37 nianchi
-rw-r--r--.1 guo root 1469 Jul 30 20:44 passwd
[root@localhostpub]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 18G 2.7G 14G 16% /
tmpfs 504M 80K 504M 1% /dev/shm
/dev/sda1 291M 33M 244M 12% /boot
[root@localhost /]# ln aming.log /boot/aming_hard
ln:creating hard link `/boot/aming_hard' => `aming.log': Invalid cross-devicelink
(硬链接,无效的跨设备链接,即不能跨分区)
软链接没有问题(可以跨分区)
[root@localhost /]# ln -s aming.log /boot/aming_hard
[root@localhost/]# ls /boot
aming_hard lost+found
config-2.6.32-431.el6.i686 symvers-2.6.32-431.el6.i686.gz
efi System.map-2.6.32-431.el6.i686
grub vmlinuz-2.6.32-431.el6.i686
initramfs-2.6.32-431.el6.i686.img
[root@localhost/]# ls -l /boot/aming_hard
lrwxrwxrwx.1 root root 9 Aug 4 18:24/boot/aming_hard -> aming.log
硬链接和软链接的区别:
硬链接不会产生新的inode节点,软链接会产生新的inode节点
删除原文件,硬链接的文件没有影响,软链接的文件会删除。
硬链接只能作用于文件,不能作用于目录;软链接即能作用于文件,又能作用于目录。
硬链接不能跨分区,软链接可以跨分区
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