Linux cheatsheet (自用)

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入门时参考了

可在官网免费下载, 从 09 年开始, 目前已经到了第五版.

常用命令

看一下 awk 和 rsync; top, nvidia-smi.

kill

Generally, you should use kill before kill -9 to give the target process a chance to clean up after itself. If you don’t give the process a chance to finish what it’s doing and clean up, it may leave corrupted files (or other state) around that it won’t be able to understand once restarted.

参考 linux - When should I not kill -9 a process? - Unix & Linux Stack Exchange

训练模型

The nohup command executes another program specified as its argument and ignores all SIGHUP (hangup) signals. SIGHUP is a signal that is sent to a process when its controlling terminal is closed.

Usually, when you run a program over SSH, if your connection drops or you log out, the session is terminated, and all the processes executed from the terminal will stop. This is where the nohup command comes in handy. It ignores all hangup signals, and the process will continue to run.

nohup COMMAND [ARGS]

通常来说

nohup python xxx.py -blahblah &
nohup sh xxx.sh -blahblah &

默认把输出保存在当前目录的 nohup.out 文件中. 最后加上 & 使命令立刻在后台运行 (书 Putting a Process in the Background 一节), 会返回一个 pid, 如果忘了也能用 ps 查看.

然后可以用

tail -f nohup.out

查看输出. 默认打印最后 10 行, 加上 -f (--follow) 表示 output appended data as the file grows.

参考

监控显存

watch -n 1 -d nvidia-smi

其中 -n (--interval) 表示更新间隔, 单位为秒, 默认 2 秒; -d (--difference) 会高亮变化. 另外, smi 是 system management interface 的缩写.

参考 Linux Watch Command | Linuxize

运行脚本

在运行脚本前修改权限 (书 Executable Permissions 一节).

chmod 755 script_filename

权限分三组, owner, group, world, 每组三个权限 rwx (read 4, write 2, execute 1), 用二进制表示再写为十进制, 则 7 (111) 就是 rwx, 5 (101) 是 r-x.

然后 for the script to run, we must precede the script name with an explicit path, 原因见书 Script File Location 一节.

./script_filename

输出到文件

参考书 Redirecting Standard Output and Standard Error to One File 一节

blahblah > output_filename.log 2>&1

We redirect file descriptor 2 (standard error) to file descriptor 1 (standard output) using the notation 2>&1. The redirection of standard error must always occur after redirecting standard output or it doesn’t work, 即 2>&1 > output_filename.log 无效.

Recent versions of bash provide a second, more streamlined method for performing this combined redirection shown here

blahblah &> output_filename.log
blahblah &>> output_filename.log

第二行是 append.

传输文件

scp [OPTION] [user@]SRC_HOST:]file1 [user@]DEST_HOST:]file2

用 -r recursively 传输文件夹.

参考 How to Use SCP Command to Securely Transfer Files | Linuxize

简单 Docker 部署

参见 Docker 部署简要.

Docker 简介可参考 这篇, 以及 Docker 底层原理浅析.

Docker 教程: 天池

先创建镜像 (image) 文件, 再基于镜像创建进程 (称为容器).

另外参考 What’s the difference between up, run, and start?

杂项

找到并 kill 相关进程

ps aux | grep "$service" | grep -v grep | awk '{print $2}' | xargs kill

参考 SC2009: Consider using pgrep instead of grepping ps output., 一个更简洁安全的写法是 (另外参考 pkill)

# When `-f` option is used, the command matches against full argument lists. 
pgrep -f "$service" | xargs kill

查看系统版本

cat /etc/os-release

conda

conda create --name myenv
conda create -n myenv python=3.8

conda remove --name myenv --all
conda env remove --name myenv

less

相比于 vim, less loads the document a page at a time.

# 显示行号
less -N /etc/init/mysql.conf
Shortcuts Action
g jump to the beginning of the file.
G end
/[string] search forward for the specified string.
n next match during a search.
N previous

vim

搜索同 less, gg 跳到文件首行, G 尾行.

Shortcuts Action
u undo
Ctrl + r redo
dd delete (cut) a line
2dd 或 d2d delete (cut) 2 lines
0 jump to the start of the line
$ jump to the end of the line

删除选中的多行

先 Shift + v 进入 visual line 模式, 移动光标选中多行, 再按 d 删除选中的多行.

多行注释

  1. 先 Ctrl + v 进入 visual block 模式, 移动光标 (之后会多行同时编辑)
  2. Shift + i (大写 I) 进入 insert 模式, 输入例如 #, 再按 Esc 退回普通模式看到效果

取消多行注释

同上 step 1 之后, 按 d 或 x 删除选中行的首字符 (多个字符需要重复多次).

删除所有

gg + dG

若粘贴的文本被自动注释

:set paste 进入粘贴模式, 再进入 insert 模式

参考 vimrc - VIM commenting out what I paste - Unix & Linux Stack Exchange