head,tail,cat,more,less

head

• image.png

• 命令演示
  [root@localhost mytest]# head -n 12 passwd.test
  1
  2
  3
  4
  5
  6
  7
  8
  9
  10
  11
  root:x:0:0:root:/root:/bin/bash
  [root@localhost mytest]# head -12 passwd.test
  1
  2
  3
  4
  5
  6
  7
  8
  9
  10
  11
  root:x:0:0:root:/root:/bin/bash

tail

• image.png

• 命令演示
  [root@localhost mytest]# tail -n 3 passwd.test
  ntp:x:38:38::/etc/ntp:/sbin/nologin
  avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
  tcpdump:x:72:72::/:/sbin/nologin
  [root@localhost mytest]#
  [root@localhost mytest]# tail -3 passwd.test
  ntp:x:38:38::/etc/ntp:/sbin/nologin
  avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
  tcpdump:x:72:72::/:/sbin/nologin

  • 另开一ssh窗口，对passwd文件进行修改
    [root@localhost mytest]# tty
    /dev/pts/4
    [root@localhost mytest]# echo 'linux centos fedora suse RHEL' >> passwd
    [root@localhost mytest]# echo 'linux centos fedora suse RHEL' >> passwd
    [root@localhost mytest]# echo 'linux centos fedora suse RHEL' >> passwd
    [root@localhost mytest]# echo 'linux centos fedora suse RHEL' >> passwd
    [root@localhost mytest]# echo 'linux centos fedora suse RHEL' >> passwd
  • 在第一个ssh窗口，执行查看命令 tail -f passwd，不会自动退出文件，可以看到文件内容在增加
    [root@localhost mytest]# tail -f passwd
    3
    4
    5
    6
    7
    8
    9
    10
    11
    linux centos fedora suse RHEL
    linux centos fedora suse RHEL
    linux centos fedora suse RHEL
    linux centos fedora suse RHEL
    linux centos fedora suse RHEL

cat

• image.png

• 命令演示
  [root@localhost mytest]# cat redhat-release
  　
  　
  　
  CentOS Linux release 7.3.1611 (Core)
  　
  　
  [root@localhost mytest]# cat version
  Linux version 3.10.0-514.el7.x86_64 (builder@kbuilder.dev.centos.org) (gcc version 4.8.5 20150623 (Red Hat 4.8.5-11) (GCC) ) #1 SMP Tue Nov 22 16:42:41 UTC 2016
  [root@localhost mytest]# cat redhat-release version
  　
  　
  　
  CentOS Linux release 7.3.1611 (Core)
  　
  　
  Linux version 3.10.0-514.el7.x86_64 (builder@kbuilder.dev.centos.org) (gcc version 4.8.5 20150623 (Red Hat 4.8.5-11) (GCC) ) #1 SMP Tue Nov 22 16:42:41 UTC 2016
  [root@localhost mytest]# cat > newfile
  my name is zhanmusi
  see you next week
  ^C
  [root@localhost mytest]#
  [root@localhost mytest]# cat newfile
  my name is zhanmusi
  see you next week
  [root@localhost mytest]# cat hebing
  cat: hebing: 没有那个文件或目录
  [root@localhost mytest]# cat redhat-release redhat-release newfile > hebing
  [root@localhost mytest]# cat hebing
  　
  　
  　
  CentOS Linux release 7.3.1611 (Core)
  　
  　
  　
  　
  　
  CentOS Linux release 7.3.1611 (Core)
  　
  　
  my name is zhanmusi
  see you next week
  [root@localhost mytest]# cat -n hebing
  1
  2
  3
  4 CentOS Linux release 7.3.1611 (Core)
  5
  6
  7
  8
  9
  10 CentOS Linux release 7.3.1611 (Core)
  11
  12
  13 my name is zhanmusi
  14 see you next week
  [root@localhost mytest]# cat -b hebing
  　
  　
  　
  1 CentOS Linux release 7.3.1611 (Core)
  　
  　
  　
  　
  　
  2 CentOS Linux release 7.3.1611 (Core)
  　
  　
  3 my name is zhanmusi
  4 see you next week
  [root@localhost mytest]# cat -E hebing
  $
  $
  $
  CentOS Linux release 7.3.1611 (Core)$
  $
  $
  $
  $
  $
  CentOS Linux release 7.3.1611 (Core)$
  $
  $
  my name is zhanmusi$
  see you next week$
  [root@localhost mytest]#

more

• image.png

• 命令演示
  [root@localhost mytest]# more -15 fstab.test
  1
  2
  3
  4
  5
  　
  　
  　
  　
  　
  # /etc/fstab
  # Created by anaconda on Tue May 30 06:31:44 2017

# Accessible filesystems, by reference, are maintained under '/dev/disk'
--More--(32%)
[root@localhost mytest]# more +5 fstab.test
5

# /etc/fstab
# Created by anaconda on Tue May 30 06:31:44 2017

# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/cl-root / xfs defaults 0 0
UUID=8be7dbe5-dde6-40b0-8900-c30f1007287e /boot xfs defaul
ts 0 0
/dev/mapper/cl-swap swap swap defaults 0 0
[root@localhost mytest]# more -s fstab.test
1
2
3
4
5

# /etc/fstab
# Created by anaconda on Tue May 30 06:31:44 2017

# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info

/dev/mapper/cl-root / xfs defaults 0 0
UUID=8be7dbe5-dde6-40b0-8900-c30f1007287e /boot xfs defaul
ts 0 0
/dev/mapper/cl-swap swap swap defaults 0 0
[root@localhost mytest]# more +/2017 fstab.test
　
...跳过

# /etc/fstab
# Created by anaconda on Tue May 30 06:31:44 2017
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info

/dev/mapper/cl-root / xfs defaults 0 0
UUID=8be7dbe5-dde6-40b0-8900-c30f1007287e /boot xfs defaul
ts 0 0
/dev/mapper/cl-swap swap swap defaults 0 0
[root@localhost mytest]# more +/4 fstab.test
　
...跳过
2
3
4
5

# /etc/fstab
# Created by anaconda on Tue May 30 06:31:44 2017

# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info

/dev/mapper/cl-root / xfs defaults 0 0
UUID=8be7dbe5-dde6-40b0-8900-c30f1007287e /boot xfs defaul
ts 0 0
/dev/mapper/cl-swap swap swap defaults 0 0
[root@localhost mytest]# cat -n fstab.test | more
1 1
2 2
3 3
4 4
5 5
6
7
8
9
10
11 #
12 # /etc/fstab
13 # Created by anaconda on Tue May 30 06:31:44 2017
14 #
15 # Accessible filesystems, by reference, are maintained under '/dev/disk'
16 # See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
17 #
18 /dev/mapper/cl-root / xfs defaults 0 0
19 UUID=8be7dbe5-dde6-40b0-8900-c30f1007287e /boot xfs defaults 0 0
20 /dev/mapper/cl-swap swap swap defaults 0 0

less

• image.png

• 命令演示
  由于more命令查看大文件后，屏幕占用效果不是很好，就不再展示详细执行过程。