2.5. 查看文件内容
查看文件：cat vi head tail more
显示时同时显示行号:
$cat -n
按页显示列表内容:
$ls -al | more
只看前10行:
$head - 10 **
显示文件第一行:
$head -1 filename
显示文件倒数第五行:
$tail -5 filename
查看两个文件间的差别:
$diff file1 file2
动态显示文本最新信息:
$tail -f crawler.log
# tail -10 ndm
818 [ 42.028236] virbr0: port 1(virbr0-nic) entered blocking state
819 [ 42.028241] virbr0: port 1(virbr0-nic) entered listening state
820 [ 42.028282] IPv6: ADDRCONF(NETDEV_UP): virbr0: link is not ready
821 [ 42.060817] virbr0: port 1(virbr0-nic) entered disabled state
822 [ 463.502594] r8169 0000:02:00.0 enp3s0: link up
823 [ 463.502608] IPv6: ADDRCONF(NETDEV_CHANGE): enp3s0: link becomes ready
824 [ 480.659625] fuse init (API version 7.22)
825 [ 493.708782] TCP: lp registered
826 [ 3366.229811] ipmi message handler version 39.2
827 [ 3366.231122] ipmi device interface
[root@linux72 yix]# head -10 ndm
1 [ 0.000000] microcode: microcode updated early to revision 0x20, date = 2018-04-10
2 [ 0.000000] Initializing cgroup subsys cpuset
3 [ 0.000000] Initializing cgroup subsys cpu
4 [ 0.000000] Initializing cgroup subsys cpuacct
5 [ 0.000000] Linux version 3.10.0-957.el7.x86_64 (mockbuild@kojibuilder-ve) (gcc version 4.8.5 20150623 (NeoKylin 4.8.5-36) (GCC) ) #1 SMP Fri Jan 11 17:34:50 CST 2019
6 [ 0.000000] Command line: BOOT_IMAGE=/vmlinuz-3.10.0-957.el7.x86_64 root=/dev/mapper/nlas-root ro crashkernel=auto rd.lvm.lv=nlas/root rd.lvm.lv=nlas/swap rhgb quiet LANG=zh_CN.UTF-8
7 [ 0.000000] e820: BIOS-provided physical RAM map:
8 [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009d7ff] usable
9 [ 0.000000] BIOS-e820: [mem 0x000000000009d800-0x000000000009ffff] reserved
10 [ 0.000000] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved
[root@linux72 yix]#
# head -1 ndm
1 [ 0.000000] microcode: microcode updated early to revision 0x20, date = 2018-04-10
# tail -1 ndm
827 [ 3366.231122] ipmi device interface
# cat -n dmes
1 [ 0.000000] microcode: microcode updated early to revision 0x20, date = 2018-04-10
2 [ 0.000000] Initializing cgroup subsys cpuset
3 [ 0.000000] Initializing cgroup subsys cpu
4 [ 0.000000] Initializing cgroup subsys cpuacct
5 [ 0.000000] Linux version 3.10.0-957.el7.x86_64 (mockbuild@kojibuilder-ve) (gcc version 4.8.5 20150623 (NeoKylin 4.8.5-36) (GCC) ) #1 SMP Fri Jan 11 17:34:50 CST 2019
6 [ 0.000000] Command line: BOOT_IMAGE=/vmlinuz-3.10.0-957.el7.x86_64 root=/dev/mapper/nlas-root ro crashkernel=auto rd.lvm.lv=nlas/root rd.lvm.lv=nl