Date：2022-08-15

指定运行级别

:::info 0：关机
1：单用户【找回丢失密码】
2：多用户状态没有网络服务
3：多用户状态有网络服务
4：系统为使用保留给用户
5：图形界面
6：系统重启 :::

常用运行级别是3和5，也可以指定默认运行级别

  1. init 0
  2. init 1
  3. //....
  5. //获取当前运行级别
  6. systemctl get-default
  7. //设置默认运行级别 reboot后生效
  8. systemctl set-default multi-user.target
  10. systemctl set-default graphical.target

找回root密码

  1. reboot
  2. 找到以 Linux16开头内容所在的行数，在行的最后输入
  3. init=/bin/sh
  4. 然后按ctrl + x进入单用户模式
  5. 在光标闪烁的位置输入：mount -o remount,rw /
  6. 输入 passwd
  7. 输入两次密码
  8. touch /.autorelabel
  9. exec /sbin/init (此过程略长，请等待)

帮助指令

man + ls help 在linux下是以 . 开头的

  1. cp code.txt copy
  3. cp sub_dir/file copy
  5. cp sub_dir/sub_dir_1/now /nobody
  7. mv code.txt temp
  9. mv code_1.txt temp/sub_dir_1
  11. mv temp/code.txt /nobody/sub_dir/code.txt
  13. mv ./target ./des/
  15. mv ./sub_dir_1/sub_dir ./sub_dir_2/
  17. mv ./sub_dir_1/temp .
  19. rm code.txt
  21. rm sub_dir/code.txt
  23. rm sub_dir_1/sub_dir_1_1/code.txt
  25. pwd 
  27. cd sub_dir
  29. pwd
  31. cd ..
  33. pwd
  36. cd sub_dir/sub_dir_2
  38. cd ..
  40. cd ../sub_dir_1/sub_dir_1_1
  42. ls
  43. ls -a
  44. ls -l
  46. diff file1 file2
  48. diff -i file1 file4
  50. diff -b file1 file3
  52. df
  53. df -a
  54. df -T
  56. name='Jack'
  58. echo name
  60. echo $name
  63. stat temp1
  65. stat -f temp1
  67. stat *
  69. cat file1
  71. awk '{print $1,$4}' file1
  73. cat file2
  75. awk -F, '{print $1,$4}' file2
  77. grep test file1
  78. ##########
  79. grep test file*
  80. ##########  
  81. grep -c test file*
  83. cat main.c
  84. grep test *.c
  85. grep -A1 test *.c
  86. grep -B1 test *.c
  88. cat file1
  89. ##########
  90. cat file2
  91. ##########
  92. comm file1 file2
  93. ##########
  94. comm file2 file1
  97. a=1,b=2
  98. let a=1,b=2
  99. let c=a+b
  100. let a++
  101. echo $a $b $c
  103. fold temp
  104. fold -w 12 temp
  105. fold -s -w 12 temp
  108. ls -l 
  109. ln temp.txt h-temp.txt
  110. ls -l
  111. ln -s /nobody/tmp /nobody/create-link-here/s-tmp
  114. find -iname "apple*"
  116. find -type f ! -size 0
  118. find sub_dir -type f -size 0 > file
  120. nl file
  121. nl file | sed '2,5c these are 2-5 contents of file'
  122. nl file | sed -n '5,70p'
  125. nl file
  126. sed 88d file
  127. nl file | sed 88,99d
  129. nl file
  130. sed 88a'Hello world!' file
  131. sed 99i'Hello world!' file
  132. nl file
  134. echo $PATH
  135. which echo
  136. which du
  138. echo "Hello world!"
  139. ##########
  140. echo '"Hello world!"'
  141. ##########
  142. echo "Hello\nworld!"
  143. ##########
  144. echo -e "Hello\nworld!"
  147. cat file
  148. ##########
  149. od -c file
  150. ##########
  151. od -t d1 file
  153. cat file
  154. ##########
  155. od file
  156. ##########
  157. od -d file
  158. ##########
  159. od -x file
  160. ##########
  161. od -A n file
  163. ls -l
  164. ##########
  165. ln -s temp.txt s-temp.txt
  166. ##########
  167. ls -l
  168. ##########
  169. ln -sb temp2.txt s-temp.txt
  171. cut -b 4 temp.txt
  172. ##########
  173. cut -b 1,2,3 temp.txt
  174. ##########
  175. cut -c 2 temp.txt
  176. ##########
  177. cut -d @ -f 1 temp.txt
  180. less file1
  181. ##########
  182. less file2
  183. ##########
  184. cmp file1 file2
  186. id
  187. ##########
  188. id -un
  189. ##########
  190. id -ur
  192. whoami
  193. id -un
  194. id -gn
  196. cut -b 4 temp.txt
  197. ##########
  198. cut -b 1,2,3 temp.txt
  199. ##########
  200. cut -c 2 temp.txt
  201. ##########
  202. cut -d @ -f 1 temp.txt
  204. comm file1 file2 -2 -3
  205. ##########
  206. comm file1 file2 -2
  207. ##########
  208. comm file1 file2 -1 -2

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