Linux - 基本命令

28 Oct 2020  (Last Update on 18 Oct 2022)

linux
Contents

在使用 Linux 常会遇到一些不太常用但又非常基本的命令，今天就来总结一下。持续更新…

系统环境 §

以下所有命令均基于 Ubuntu 18.04 amd64 版本以及 CentOS 7.8 amd64。不保证在其它发行版上的正确性。但是在通常情况下是通用的。

查询系统信息 §

基本信息 §

  • 系统位数

    • Ubuntu

      $ getconf LONG_BIT
64
$ file /bin/ls
/bin/ls: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=9567f9a28e66f4d7ec4baf31cfbf68d0410f0ae6, stripped

    • CentOS

      $ getconf LONG_BIT
64
$ file /bin/ls
/bin/ls: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, BuildID[sha1]=aaf05615b6c91d3cbb076af81aeff531c5d7dfd9, stripped

  • 系统内核版本信息

    • Ubuntu

      $ uname -a
Linux iZ2zehx4vggo1gk4clxdy2Z 4.15.0-48-generic #51-Ubuntu SMP Wed Apr 3 08:28:49 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

    • CentOS

      $ uname -a
Linux iz2zefu8x0w8a73lncvuicz 3.10.0-1127.13.1.el7.x86_64 #1 SMP Tue Jun 23 15:46:38 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

  • 系统内核版本、编译等信息

    • Ubuntu

      $ cat /proc/version
Linux version 4.15.0-48-generic (buildd@lgw01-amd64-036) (gcc version 7.3.0 (Ubuntu 7.3.0-16ubuntu3)) #51-Ubuntu SMP Wed Apr 3 08:28:49 UTC 2019

    • CentOS

      $ cat /proc/version
Linux version 3.10.0-1127.13.1.el7.x86_64 (mockbuild@kbuilder.bsys.centos.org) (gcc version 4.8.5 20150623 (Red Hat 4.8.5-39) (GCC) ) #1 SMP Tue Jun 23 15:46:38 UTC 2020

  • 系统内核模块加载信息

    • Ubuntu

      $ lsmod
Module                  Size  Used by
btrfs                1122304  0
zstd_compress         163840  1 btrfs
xor                    24576  1 btrfs
raid6_pq              114688  1 btrfs
ufs                    77824  0
qnx4                   16384  0
...

    • CentOS

      $ lsmod
Module                  Size  Used by
xt_nat                 12681  6 
binfmt_misc            17468  1 
veth                   13458  0 
xt_conntrack           12760  2 
ipt_MASQUERADE         12678  4 
nf_nat_masquerade_ipv4    13463  1 ipt_MASQUERADE

  • 查看系统发行版本信息

    • Ubuntu

      $ lsb_release -a
LSB Version:    core-9.20170808ubuntu1-noarch:security-9.20170808ubuntu1-noarch
Distributor ID: Ubuntu
Description:    Ubuntu 18.04.5 LTS
Release:        18.04
Codename:       bionic
$ cat /etc/issue
Ubuntu 18.04.5 LTS \n \l

    • CentOS

      $ lsb_release -a
LSB Version:    :core-4.1-amd64:core-4.1-noarch
Distributor ID: CentOS
Description:    CentOS Linux release 7.8.2003 (Core)
Release:        7.8.2003
Codename:       Core
$ cat /etc/redhat-release
CentOS Linux release 7.8.2003 (Core)

  • 开机时间、用户数、平均负载信息

    • Ubuntu

      $ uptime
 11:12:30 up 47 days, 49 min,  1 user,  load average: 0.00, 0.00, 0.00

    • CentOS

      $ uptime
 11:13:14 up 68 days,  1:24,  1 user,  load average: 0.00, 0.01, 0.05

硬件信息 §

  • 查看 CPU 信息

    • Ubuntu

      # 基本信息
$ 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:               85
Model name:          Intel(R) Xeon(R) Platinum 8163 CPU @ 2.50GHz
Stepping:            4
CPU MHz:             2499.998
BogoMIPS:            4999.99
Hypervisor vendor:   KVM
Virtualization type: full
L1d cache:           32K
L1i cache:           32K
L2 cache:            1024K
L3 cache:            33792K
NUMA node0 CPU(s):   0
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 rep_good nopl nonstop_tsc cpuid 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 3dnowprefetch invpcid_single pti ibrs ibpb stibp fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm mpx avx512f avx512dq rdseed adx smap avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 arat
# 详细信息，精确到每一核
$ cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 85
model name      : Intel(R) Xeon(R) Platinum 8163 CPU @ 2.50GHz
stepping        : 4
microcode       : 0x1
cpu MHz         : 2499.998
cache size      : 33792 KB
physical id     : 0
siblings        : 1
core id         : 0
cpu cores       : 1
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 rep_good nopl nonstop_tsc cpuid 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 3dnowprefetch invpcid_single pti ibrs ibpb stibp fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm mpx avx512f avx512dq rdseed adx smap avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 arat
bugs            : cpu_meltdown spectre_v1 spectre_v2 spec_store_bypass l1tf
bogomips        : 4999.99
clflush size    : 64
cache_alignment : 64
address sizes   : 46 bits physical, 48 bits virtual
power management:
...

    • CentOS

      # 基本信息
$ 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:    2
Core(s) per socket:    2
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 85
Model name:            Intel(R) Xeon(R) Platinum 8269CY CPU @ 2.50GHz
Stepping:              7
CPU MHz:               2500.000
BogoMIPS:              5000.00
Hypervisor vendor:     KVM
Virtualization type:   full
L1d cache:             32K
L1i cache:             32K
L2 cache:              1024K
L3 cache:              36608K
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 rep_good nopl 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 3dnowprefetch invpcid_single fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm mpx avx512f avx512dq rdseed adx smap avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 arat avx512_vnni
# 详细信息，精确到每一核
$ cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 85
model name      : Intel(R) Xeon(R) Platinum 8269CY CPU @ 2.50GHz
stepping        : 7
microcode       : 0x1
cpu MHz         : 2500.000
cache size      : 36608 KB
physical id     : 0
siblings        : 4
core id         : 0
cpu cores       : 2
apicid          : 0
initial apicid  : 0
fpu             : yes
fpu_exception   : yes
cpuid level     : 22
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 rep_good nopl 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 3dnowprefetch invpcid_single fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm mpx avx512f avx512dq rdseed adx smap avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 arat avx512_vnni
bogomips        : 5000.00
clflush size    : 64
cache_alignment : 64
address sizes   : 46 bits physical, 48 bits virtual
power management:
...

  • 内存信息

    • Ubuntu

      $ free -m
              total        used        free      shared  buff/cache   available
Mem:           1993         560          96           1        1336        1249
Swap:           947           6         940
$ cat /proc/meminfo
MemTotal:        7733000 kB
MemFree:         2780720 kB
MemAvailable:    5848968 kB
Buffers:          284336 kB
Cached:          2817548 kB
SwapCached:            0 kB
Active:          3272980 kB
Inactive:        1291048 kB
Active(anon):    1462416 kB
Inactive(anon):      264 kB
Active(file):    1810564 kB
Inactive(file):  1290784 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:             0 kB
SwapFree:              0 kB
Dirty:                24 kB
Writeback:             0 kB
AnonPages:       1462140 kB
Mapped:           117640 kB
Shmem:               540 kB
Slab:             292916 kB
SReclaimable:     271868 kB
SUnreclaim:        21048 kB
KernelStack:        3696 kB
PageTables:         7240 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:     3866500 kB
Committed_AS:    2402088 kB
VmallocTotal:   34359738367 kB
VmallocUsed:       19948 kB
VmallocChunk:   34359712252 kB
Percpu:              800 kB
HardwareCorrupted:     0 kB
AnonHugePages:   1230848 kB
CmaTotal:              0 kB
CmaFree:               0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
DirectMap4k:       96952 kB
DirectMap2M:     2768896 kB
DirectMap1G:     5242880 kB

    • CentOS

      $ free -m
              total        used        free      shared  buff/cache   available
Mem:           7551        1541        2715           0        3294        5711
Swap:             0           0           0
$ cat /proc/meminfo
MemTotal:        7733000 kB
MemFree:         2781092 kB
MemAvailable:    5849356 kB
Buffers:          284336 kB
Cached:          2817568 kB
SwapCached:            0 kB
Active:          3273048 kB
Inactive:        1291032 kB
Active(anon):    1462452 kB
Inactive(anon):      264 kB
Active(file):    1810596 kB
Inactive(file):  1290768 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:             0 kB
SwapFree:              0 kB
Dirty:                24 kB
Writeback:             0 kB
AnonPages:       1462208 kB
Mapped:           117640 kB
Shmem:               540 kB
Slab:             292884 kB
SReclaimable:     271868 kB
SUnreclaim:        21016 kB
KernelStack:        3696 kB
PageTables:         7240 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:     3866500 kB
Committed_AS:    2402088 kB
VmallocTotal:   34359738367 kB
VmallocUsed:       19948 kB
VmallocChunk:   34359712252 kB
Percpu:              800 kB
HardwareCorrupted:     0 kB
AnonHugePages:   1230848 kB
CmaTotal:              0 kB
CmaFree:               0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
DirectMap4k:       96952 kB
DirectMap2M:     2768896 kB
DirectMap1G:     5242880 kB

  • 磁盘信息

    • Ubuntu

      $ lsblk
NAME   MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vda    252:0    0  40G  0 disk 
└─vda1 252:1    0  40G  0 part /
$ df
Filesystem     1K-blocks     Used Available Use% Mounted on
udev              998184        0    998184   0% /dev
tmpfs             204124     6704    197420   4% /run
/dev/vda1       41152812 10847444  28401712  28% /
tmpfs            1020608        0   1020608   0% /dev/shm
tmpfs               5120        0      5120   0% /run/lock
tmpfs            1020608        0   1020608   0% /sys/fs/cgroup
overlay         41152812 10847444  28401712  28% /var/lib/docker/overlay2/be844ce0c2b9815231c6cacfbe3c23a95bc3f60178dd1d47ccd0193e534eae33/merged
tmpfs             204120        0    204120   0% /run/user/0
$ fdisk -l
Disk /dev/vda: 40 GiB, 42949672960 bytes, 83886080 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xfec7dc5a
    
Device     Boot Start      End  Sectors Size Id Type
/dev/vda1  *     2048 83886046 83883999  40G 83 Linux
# 磁盘读写速度
$ iostat
Linux 4.15.0-48-generic (iZ2zehx4vggo1gk4clxdy2Z)       10/28/2020      _x86_64_        (1 CPU)
    
avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.59    0.00    0.45    0.02    0.00   98.94
    
Device             tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
vda               0.57         0.97         4.55    3912031   18372393

    • CentOS

      $ lsblk
NAME   MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vda    253:0    0  40G  0 disk 
└─vda1 253:1    0  40G  0 part /
$ df
Filesystem     1K-blocks    Used Available Use% Mounted on
devtmpfs         3856184       0   3856184   0% /dev
tmpfs            3866500       0   3866500   0% /dev/shm
tmpfs            3866500     540   3865960   1% /run
tmpfs            3866500       0   3866500   0% /sys/fs/cgroup
/dev/vda1       41151808 8950652  30087724  23% /
tmpfs             773300       0    773300   0% /run/user/0
overlay         41151808 8950652  30087724  23% /var/lib/docker/overlay2/33222ef47484c66c3b4e48b0d57fb3bd8584894c8751c011c8894f545a9e2e09/merged
$ fdisk -l
    
Disk /dev/vda: 42.9 GB, 42949672960 bytes, 83886080 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x0008de3e
    
   Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *        2048    83884031    41940992   83  Linux
# 磁盘读写速度
$ iostat
Linux 3.10.0-1127.13.1.el7.x86_64 (iz2zefu8x0w8a73lncvuicz)     10/28/2020      _x86_64_        (4 CPU)
    
avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.09    0.00    0.07    0.00    0.00   99.84
    
Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
vda               0.23         0.11         1.99     676105   11672940

  • PCI 设备信息

    • Ubuntu

      $ lspci -tv
-[0000:00]-+-00.0  Intel Corporation 440FX - 82441FX PMC [Natoma]
           +-01.0  Intel Corporation 82371SB PIIX3 ISA [Natoma/Triton II]
           +-01.1  Intel Corporation 82371SB PIIX3 IDE [Natoma/Triton II]
           +-01.2  Intel Corporation 82371SB PIIX3 USB [Natoma/Triton II]
           +-01.3  Intel Corporation 82371AB/EB/MB PIIX4 ACPI
           +-02.0  Cirrus Logic GD 5446
           +-03.0  Red Hat, Inc. Virtio network device
           +-04.0  Red Hat, Inc. Virtio console
           +-05.0  Red Hat, Inc. Virtio block device
           \-06.0  Red Hat, Inc. Virtio memory balloon

    • CentOS

      $ lspci -tv
-[0000:00]-+-00.0  Intel Corporation 440FX - 82441FX PMC [Natoma]
           +-01.0  Intel Corporation 82371SB PIIX3 ISA [Natoma/Triton II]
           +-01.1  Intel Corporation 82371SB PIIX3 IDE [Natoma/Triton II]
           +-01.2  Intel Corporation 82371SB PIIX3 USB [Natoma/Triton II]
           +-01.3  Intel Corporation 82371AB/EB/MB PIIX4 ACPI
           +-02.0  Cirrus Logic GD 5446
           +-03.0  Red Hat, Inc. Virtio console
           +-04.0  Red Hat, Inc. Virtio block device
           +-05.0  Red Hat, Inc. Virtio network device
           \-06.0  Red Hat, Inc. Virtio memory balloon

  • USB 设备信息

    • Ubuntu

      $ lsusb -tv
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
    |__ Port 1: Dev 2, If 0, Class=Human Interface Device, Driver=usbhid, 12M

系统配置 §

设置默认 Shell §

查看当前 Shell：

$ echo $SHELL

查看用户默认 Shell：

$ cat /etc/passwd | grep $(whoami)

列举所有可用 Shell：

$ cat /etc/shells

使用 usermod 命令更改默认 Shell：

$ sudo usermod --shell /usr/bin/fish <username>

使用 chsh 命令更改默认 Shell：

$ chsh -s /usr/bin/fish <username>

除此之外，我们也可以通过直接修改 /etc/passwd 对应的字段来修改默认 Shell，但是直接对该文件进行修改可能会带来一些风险。

常用工具 §

我们也可以使用一些 CLI 的 Cheatsheet 工具，来获取这些常用工具的基本用法。具体可以参考我的另一篇文章。

压缩 / 解压缩 §

  • .zip

    • 压缩

      $ zip demo.zip ./demo_a ./demo_b

    • 解压

      $ unzip demo.zip

    更多参数请参考相关命令说明手册

  • .tar

    • 压缩

      $ tar -cvf demo.tar ./demo_a ./demo_b

    • 解压

      $ tar -xvf demo.tar

    更多参数请参考相关命令说明手册

  • tar.gz

    • 压缩

      $ tar -zcvf demo.tar.gz ./demo_a ./demo_b

    • 解压

      $ tar -zxvf demo.tar.gz

    更多参数请参考相关命令说明手册

图片处理 §

Linux 平台有很多用于处理图片的工具，例如ImageMagick、jpegoptim 和 pngcrush 等。这里主要介绍 ImageMagick 的用法。

  • ImageMagick 介绍：

    • ImageMagick 官网
    • 使用 ImageMagick 的创建，编辑，撰写，或转换位图图像。它可以读取和写入各种格式（超过200种）的图像，包括 PNG，JPEG，GIF，HEIC，TIFF，DPX，EXR，WebP，Postscript，PDF 和 SVG。使用ImageMagick可以调整图像大小，翻转，镜像，旋转，变形，剪切和变换图像，调整图像颜色，应用各种特殊效果或绘制文本，线条，多边形，椭圆和贝塞尔曲线。

  • ImageMagick 安装：

    • 本地 apt 安装：

      $ apt install imagemagick

    • 官网下载即用型二进制文件：

      $ wget https://download.imagemagick.org/ImageMagick/download/binaries/magick

    注意：由于 apt 安装的 ImageMagick 版本为7以下版本，故不支持 magick 命令，依旧需要使用诸如 convert、identify 和 animate 等字命令来进行工作

  • ImageMagick 样例：

    • 转换格式：

      $ convert xxx.jpeg xxx.png

    • 压缩图片：

      # 将图片像素改为1920*1080
$ convert -resize 1920x1080 xxx.jpeg xxx.jpeg
# 将图片压缩为原来的50%*50%
$ convert -sample 50%x50% xxx.jpeg xxx.jpeg
# 使用 -quality 参数控制压缩图片的质量，参数值可以是0～100之间的任意数
$ convert -resize 500x500 -quality 75 xxx.jpeg xxx.jpeg

    • 批量压缩图片：

      # 压缩当前目录下所有后缀名包含在列表中的图片
$ find ./ -regex '.*\(jpg\|JPG\|png\|PNG\|jpeg\)' -size +50k -exec convert -resize 100x100 {} {} \;

远程连接 §

  • SSH 连接远程主机：

    $ ssh root@112.113.114.115 # 以 root 用户身份登陆 112.113.114.115 IP 对应的远程主机
$ ssh user@myhost.com # 以 user 用户身份登陆 myhost.com 域名对应的远程主机

  • 向（从）远程主机复制文件：

    $ scp ~/myfile.txt root@112.113.114.115:/root/CopyFiles/ # 将本机主目录下的 myfile.txt 复制到以 root 身份登陆的 112.113.114.115 IP 对应的远程主机的 /root/CopyFiles/ 目录下
$ scp user@myhost.com:/home/user/myfile.txt ~/CopyFiles/ # 将以 root 身份登陆的 112.113.114.115 IP 对应的远程主机的 /home/user/myfile.txt 复制到本机主目录的 CopyFiles 目录下

参考 §