linux 环境命令随记

sh: steve bourne
bash: bourne-again shell, gpl, centos和ubuntu 默认使用
csh: c shell,C语言风格
tcsh
ksh：korb shell,aix默认shell
zsh: macos 默认shell

bash shell
GNU Bourne-Again Shell(bash)是GNU计划中重要的工具软件之一，目前也是linux标准的shell,也sh兼容

显示使用的shell

显示当前使用的shell
[root@localhost ~]# echo ${SHELL}
/bin/bash
显示当前系统中所有使用的shell
[root@localhost ~]# cat /etc/shells
/bin/sh
/bin/bash
/sbin/nologin
/usr/bin/sh
/usr/bin/bash
/usr/sbin/nologin

设置主机名：

[root@localhost ~]# hostnamectl set-hostname ccp
[root@localhost ~]# hostname ccq

shell中可执行的两类命令
内部命令：由shell自带，而却通过命令形式提供，用户登录后自动加载并常驻内存中
外部命令：在文件系统路径下有对应的可执行程序文件，当执行命令行是才从磁盘加载至内存中，执行完毕后从内部中删除

区别指定的命令是内部或者是外部命令
type COMMAND

[root@localhost ~]# type -a echo
echo is a shell builtin
echo is /usr/bin/echo

内部命令相关

help 内部命令略表
enable 管理内部命令
enable cmd 启动内部命令
enable -n cmd禁用内部命令
enable -n 查看所有禁用的内部命令

执行外部命令

which -a | --skip-alias
whereis

hash缓存

系统hash表未空，当外部命令执行时，默认会从path路径下寻找命令，找到后会将这条命令的路径记录到hash表中，当再次使用该命令时，shell解释器首先会查看hash表，存在将执行之，如果不存在降回去PATH路径下寻找，利用hash缓存表可大大提高命令的调用速率
hash命令常见用法
hash 显示hash缓存
hash -l 显示hash缓存，可作为输入使用
hash -p path name 经命令全路径 path 起别名为name
hash -t name 打印缓存中name的路径
hash -d name 清除name缓存
hash -r 清除全部缓存

查看硬件信息
1、查看cpu
lscpu命令可以查看cpu信息
cat /proc/cpuinfo 也可以看到

[root@localhost ~]# lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                4
On-line CPU(s) list:   0-3
Thread(s) per core:    1
Core(s) per socket:    2
Socket(s):             2
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 60
Model name:            Intel(R) Core(TM) i5-4200H CPU @ 2.80GHz
Stepping:              3
CPU MHz:               2793.547
BogoMIPS:              5587.09
Hypervisor vendor:     VMware
Virtualization type:   full
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              3072K
NUMA node0 CPU(s):     0-3
Flags:                 fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon nopl xtopology tsc_reliable nonstop_tsc eagerfpu pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm fsgsbase tsc_adjust bmi1 avx2 smep bmi2 invpcid xsaveopt ibpb ibrs stibp arat spec_ctrl intel_stibp arch_capabilities

[root@localhost ~]# cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 60
model name      : Intel(R) Core(TM) i5-4200H CPU @ 2.80GHz
stepping        : 3
microcode       : 0x25
cpu MHz         : 2793.547
cache size      : 3072 KB
physical id     : 0
siblings        : 2
core id         : 0
cpu cores       : 2
apicid          : 0
initial apicid  : 0
fpu             : yes
fpu_exception   : yes
cpuid level     : 13
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon nopl xtopology tsc_reliable nonstop_tsc eagerfpu pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm fsgsbase tsc_adjust bmi1 avx2 smep bmi2 invpcid xsaveopt ibpb ibrs stibp arat spec_ctrl intel_stibp arch_capabilities
bogomips        : 5587.09
clflush size    : 64
cache_alignment : 64
address sizes   : 43 bits physical, 48 bits virtual
power management:

processor       : 1
vendor_id       : GenuineIntel
cpu family      : 6
model           : 60
model name      : Intel(R) Core(TM) i5-4200H CPU @ 2.80GHz
stepping        : 3
microcode       : 0x25
cpu MHz         : 2793.547
cache size      : 3072 KB
physical id     : 0
siblings        : 2
core id         : 1
cpu cores       : 2
apicid          : 1
initial apicid  : 1
fpu             : yes
fpu_exception   : yes
cpuid level     : 13
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon nopl xtopology tsc_reliable nonstop_tsc eagerfpu pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm fsgsbase tsc_adjust bmi1 avx2 smep bmi2 invpcid xsaveopt ibpb ibrs stibp arat spec_ctrl intel_stibp arch_capabilities
bogomips        : 5587.09
clflush size    : 64
cache_alignment : 64
address sizes   : 43 bits physical, 48 bits virtual
power management:

processor       : 2
vendor_id       : GenuineIntel
cpu family      : 6
model           : 60
model name      : Intel(R) Core(TM) i5-4200H CPU @ 2.80GHz
stepping        : 3
microcode       : 0x25
cpu MHz         : 2793.547
cache size      : 3072 KB
physical id     : 1
siblings        : 2
core id         : 0
cpu cores       : 2
apicid          : 2
initial apicid  : 2
fpu             : yes
fpu_exception   : yes
cpuid level     : 13
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon nopl xtopology tsc_reliable nonstop_tsc eagerfpu pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm fsgsbase tsc_adjust bmi1 avx2 smep bmi2 invpcid xsaveopt ibpb ibrs stibp arat spec_ctrl intel_stibp arch_capabilities
bogomips        : 5587.09
clflush size    : 64
cache_alignment : 64
address sizes   : 43 bits physical, 48 bits virtual
power management:

processor       : 3
vendor_id       : GenuineIntel
cpu family      : 6
model           : 60
model name      : Intel(R) Core(TM) i5-4200H CPU @ 2.80GHz
stepping        : 3
microcode       : 0x25
cpu MHz         : 2793.547
cache size      : 3072 KB
physical id     : 1
siblings        : 2
core id         : 1
cpu cores       : 2
apicid          : 3
initial apicid  : 3
fpu             : yes
fpu_exception   : yes
cpuid level     : 13
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon nopl xtopology tsc_reliable nonstop_tsc eagerfpu pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm fsgsbase tsc_adjust bmi1 avx2 smep bmi2 invpcid xsaveopt ibpb ibrs stibp arat spec_ctrl intel_stibp arch_capabilities
bogomips        : 5587.09
clflush size    : 64
cache_alignment : 64
address sizes   : 43 bits physical, 48 bits virtual
power management:

2、查看内存大小
free
car /proc/meminfo

[root@localhost ~]# free
              total        used        free      shared  buff/cache   available
Mem:        3863568      176912     3106372       11904      580284     3393768
Swap:       2097148           0     2097148
[root@localhost ~]# cat /proc/meminfo
MemTotal:        3863568 kB
MemFree:         3106348 kB
MemAvailable:    3393764 kB
Buffers:            2108 kB
Cached:           478264 kB
SwapCached:            0 kB
Active:           342312 kB
Inactive:         206596 kB
Active(anon):      69316 kB
Inactive(anon):    11124 kB
Active(file):     272996 kB
Inactive(file):   195472 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:       2097148 kB
SwapFree:        2097148 kB
Dirty:                 0 kB
Writeback:             0 kB
AnonPages:         68536 kB
Mapped:            25216 kB
Shmem:             11904 kB
Slab:              99932 kB
SReclaimable:      47132 kB
SUnreclaim:        52800 kB
KernelStack:        4368 kB
PageTables:         4548 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:     4028932 kB
Committed_AS:     300204 kB
VmallocTotal:   34359738367 kB
VmallocUsed:      201340 kB
VmallocChunk:   34359310332 kB
HardwareCorrupted:     0 kB
AnonHugePages:     10240 kB
CmaTotal:              0 kB
CmaFree:               0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
DirectMap4k:      106304 kB
DirectMap2M:     4087808 kB
DirectMap1G:     2097152 kB

3、查看硬盘分区情况

[root@localhost ~]# lsblk
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda               8:0    0   30G  0 disk
├─sda1            8:1    0    2M  0 part
├─sda2            8:2    0    1G  0 part /boot
└─sda3            8:3    0   26G  0 part
  ├─centos-root 253:0    0   20G  0 lvm  /
  ├─centos-swap 253:1    0    2G  0 lvm  [SWAP]
  └─centos-home 253:2    0    4G  0 lvm  /home
sr0              11:0    1 1024M  0 rom
[root@localhost ~]# car /proc/partitions
-bash: car: command not found
[root@localhost ~]# cat /proc/partitions
major minor  #blocks  name

   8        0   31457280 sda
   8        1       2048 sda1
   8        2    1048576 sda2
   8        3   27270144 sda3
  11        0    1048575 sr0
 253        0   20971520 dm-0
 253        1    2097152 dm-1
 253        2    4194304 dm-2

查看系统版本信息
查看内核版本

[root@localhost ~]# uname -a
Linux ccq 3.10.0-862.el7.x86_64 #1 SMP Fri Apr 20 16:44:24 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
[root@localhost ~]# uname -r
3.10.0-862.el7.x86_64

查看系统发行版本

[root@localhost ~]# cat /etc/redhat-release
CentOS Linux release 7.5.1804 (Core)
[root@localhost ~]# cat /etc/os-release
NAME="CentOS Linux"
VERSION="7 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="7"
PRETTY_NAME="CentOS Linux 7 (Core)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:7"
HOME_URL="https://www.centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"

CENTOS_MANTISBT_PROJECT="CentOS-7"
CENTOS_MANTISBT_PROJECT_VERSION="7"
REDHAT_SUPPORT_PRODUCT="centos"
REDHAT_SUPPORT_PRODUCT_VERSION="7"