Linux基礎命令 2017-07-12日課

bc, lscpu, free, dd, rpm, lsblk, ldd, file, hexdump, uname, sha1sum, sha256sum, md5sum

bc
an arbitrary precision language
- scale=NUM ; precision
- quit

lscpu
display information about the CPU

[root@localhost ~]# lscpu
Architecture:          x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order:            Little Endian
CPU(s): 1 On-line CPU(s) list: 0 Thread(s) per core: 1 Core(s) per socket: 1 Socket(s): 1 NUMA node(s): 1 Vendor ID:             GenuineIntel
CPU family: 6 Model: 58 Model name:            Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz
Stepping: 9 CPU MHz: 2493.655 BogoMIPS: 4988.79 Hypervisor vendor:     VMware
Virtualization type:   full
L1d cache: 32K
L1i cache: 32K
L2 cache: 256K
L3 cache: 3072K
NUMA node0 CPU(s): 0

free
Display the amount of the memory

[root@localhost ~]# free total        used free shared  buff/cache   available
Mem: 999936 567492 108228 5096 324216 217416 Swap: 2097148 19584 2077564

dd
convert and copy file
Syntax: dd if=SourceDir of=DestinationDir [Operands]
- Operands
  - bs=BYTERS Read and Write bytes at a time
  - ibs=BYTERS Read bytes at a time
  - obs=BYTERS Write bytes at a time
  - count=NUM
```
[root@localhost ~]# dd if=/dev/zero of=1.txt obs=512 count=1000 1000+0 records in 1000+0 records out 512000 bytes (512 kB) copied, 0.00366222 s, 140 MB/s
```
RAM/ROM
RAM : Random Access Memory
ROM: Read Only Memory

rpm
rpm {-q|–query} {select-options}

select-options

-i/–info Display package information

[root@localhost ~]# rpm -qi kernel Name        : kernel
Version     : 3.10.0 Release     : 514.el7
Architecture: x86_64
Install Date: Tue 11 Jul 2017 01:36:08 AM PDT
Group       : System Environment/Kernel
Size        : 154799976 License     : GPLv2
Signature   : RSA/SHA256, Tue 22 Nov 2016 06:19:35 PM PST, Key ID 24c6a8a7f4a80eb5
Source RPM  : kernel-3.10.0-514.el7.src.rpm
Build Date  : Tue 22 Nov 2016 09:33:33 AM PST
Build Host  : kbuilder.dev.centos.org
Relocations : (not relocatable)
Packager    : CentOS BuildSystem <http://bugs.centos.org> Vendor      : CentOS
URL         : http://www.kernel.org/ Summary     : The Linux kernel
Description : The kernel package contains the Linux kernel (vmlinuz), the core of any
Linux operating system.  The kernel handles the basic functions
of the operating system: memory allocation, process allocation, device
input and output, etc.

lsblk

[root@localhost ~]# lsblk NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda 8:0 0 20G 0 disk 
├─sda1 8:1 0 300M 0 part /boot
├─sda2 8:2 0 2G 0 part [SWAP]
└─sda3 8:3 0 17.7G 0 part /
sr0 11:0 1 1024M 0 rom

ldd
print shared library dependences

[root@localhost ~]# clear [root@localhost ~]# ldd /bin/cat linux-vdso.so.1 =>  (0x00007ffd09bbe000)
 libc.so.6 => /lib64/libc.so.6 (0x00007f4d2ecb2000)
 /lib64/ld-linux-x86-64.so.2 (0x00007f4d2f087000)
[root@localhost ~]# ldd /bin/ls linux-vdso.so.1 =>  (0x00007fff6e73d000)
 libselinux.so.1 => /lib64/libselinux.so.1 (0x00007ffac5601000)
 libcap.so.2 => /lib64/libcap.so.2 (0x00007ffac53fc000)
 libacl.so.1 => /lib64/libacl.so.1 (0x00007ffac51f2000)
 libc.so.6 => /lib64/libc.so.6 (0x00007ffac4e31000)
 libpcre.so.1 => /lib64/libpcre.so.1 (0x00007ffac4bd0000)
 libdl.so.2 => /lib64/libdl.so.2 (0x00007ffac49cb000)
 /lib64/ld-linux-x86-64.so.2 (0x00007ffac583c000)
 libattr.so.1 => /lib64/libattr.so.1 (0x00007ffac47c6000)
 libpthread.so.0 => /lib64/libpthread.so.0 (0x00007ffac45aa000)

file
determine the file type

[root@localhost ~]# file /etc/passwd
/etc/passwd: ASCII text [root@localhost ~]# file /bin/cat
/bin/cat: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, BuildID[sha1]=fac04659ab9a437b5384c09f4731023373821a39, stripped [root@localhost ~]# file notepad.exe 
notepad.exe: MS-DOS executable

hexdump 讀取16進制文件

[root@localhost ~]# hexdump -C notepad.exe | head -n 10 00000000 4d 5a 90 00 03 00 00 00 04 00 00 00 ff ff 00 00 |MZ..............| 00000010 b8 00 00 00 00 00 00 00 40 00 00 00 00 00 00 00 |........@.......| 00000020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 00000030 00 00 00 00 00 00 00 00 00 00 00 00 e8 00 00 00 |................| 00000040 0e 1f ba 0e 00 b4 09 cd 21 b8 01 4c cd 21 54 68 |........!..L.!Th| 00000050 69 73 20 70 72 6f 67 72 61 6d 20 63 61 6e 6e 6f |is program canno| 00000060 74 20 62 65 20 72 75 6e 20 69 6e 20 44 4f 53 20 |t be run in DOS | 00000070 6d 6f 64 65 2e 0d 0a 24 00 00 00 00 00 00 00 83 |mode...$........| 00000080 c2 32 29 c7 a3 5c 7a c7  a3 5c 7a c7 a3 5c 7a ce  |.2)..\z..\z..\z.| 00000090 db d8 7a c6 a3 5c 7a ce  db c9 7a c5 a3 5c 7a ce  |..z..\z...z..\z.|

uname [options]

-a all
-r release

-k kernel name

[root@zb01 ~]# uname -s Linux
[root@zb01 ~]# uname -r 2.6.32-696.el6.x86_64
[root@zb01 ~]# uname -a Linux zb01 2.6.32-696.el6.x86_64 #1 SMP Tue Mar 21 19:29:05 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

使用sha1sum, sha256sum 或 md5sum校驗CentOS-6.9-x86_64-bin-DVD1.iso光盤是否完整，若校驗碼與以下相同則說明光盤完整。
以下為從http://mirrors.163.com/centos/6.9/isos/x86_64t讀取的校驗碼
- sha1
  09c68654986feee54dcc6cad72771b7fe4be9703 CentOS-6.9-x86_64-bin-DVD1.iso
- sha256
  d27cf37a40509c17ad70f37bc743f038c1feba00476fe6b69682aa424c399ea6 CentOS-6.9-x86_64-bin-DVD1.iso
- md5sum
  2e227fa14c8a9791293b6525289c7dad CentOS-6.9-x86_64-bin-DVD1.iso
```
[root@zb01 ~]# sha1sum /dev/sr0 09c68654986feee54dcc6cad72771b7fe4be9703  /dev/sr0 [root@zb01 ~]# md5sum /dev/sr0 2e227fa14c8a9791293b6525289c7dad  /dev/sr0 [root@zb01 ~]# sha256sum /dev/sr0 d27cf37a40509c17ad70f37bc743f038c1feba00476fe6b69682aa424c399ea6  /dev/sr0
```