UCB-Sysadmin 笔记

Linux System Administration Decal

A course covering the basics of setting up and administering a production-quality Linux server environment.

Lab1

找出隐藏文件

ls -a

连接输出，然后删除文件

cat naming_is_hard* | xargs
#s t a n f o r d > b e r k e l e y
rm -rf nonsense/

从大文件里面找东西(-A是之后，``-B`是之前)

grep "http" -C 2 big_data.txt

增加执行权限

chmod +x a_script

查看文件详细，时间倒序

ls -ltr

cat foo > out.txt和cat foo >> out.txt的区别: 前者覆盖，后者追加

用head打印前几行(-n 选项用于指定要显示的行数)

head -n 4 big_data.txt

Lab2

Vim

Vim: cheat sheet

删除10行: d10

暂停Vim，然后重新进入Ctrl-Z，然后fg %i其中i是实际进程数

同时编辑多个文件

# 分成上下两部分 用Ctrl+W和jk(或者箭头)进行上下切换
:split filename2
# 左右
:vsplit filename2

缩进: 先把光标停在要缩进的地方，然后Shift+V进入可视模式，上下移动箭头选择，然后用>或者<缩进

tmux

cheat sheet

拆分: Ctrl-b % (左右两个) or Ctrl-b " (上下两个)

退出: Ctrl-D

列出当前session: tmux ls

回到指定session: tmux a -t filename

终止指定session: tmux kill-session -t filename

进入新的session: tmux new -s filename

phonebook实验

#!/bin/bash

PHONEBOOK_ENTRIES="bash_phonebook_entries"


if [ "$#" -lt 1 ]; then
    exit 1

elif [ "$1" = "new" ]; then
    # YOUR CODE HERE #
    if [ "$#" -ne 3 ]; then
        echo "Usage: ./phonebook.sh new <name> <number>"
        exit 1
    else
        echo "$2 $3" >> $PHONEBOOK_ENTRIES
    fi

elif [ "$1" = "list" ]; then
    if [ ! -e $PHONEBOOK_ENTRIES ] || [ ! -s $PHONEBOOK_ENTRIES ]; then
        echo "phonebook is empty"
    else
        # YOUR CODE HERE #
        sed -n 'p' $PHONEBOOK_ENTRIES
    fi

elif [ "$1" = "lookup" ]; then
    # YOUR CODE HERE #
    if [ "$#" -ne 2 ]; then
        echo "Usage: ./phonebook.sh lookup <name>"
        exit 1
    else
        sed -n "/$2 [0-9]/p" $PHONEBOOK_ENTRIES
    fi

elif [ "$1" = "remove" ]; then
    # YOUR CODE HERE #
    if [ "$#" -ne 2 ]; then
        echo "Usage: ./phonebook.sh remove <name>"
        exit 1
    else
        sed -i "/$2 [0-9]+/d" $PHONEBOOK_ENTRIES
    fi

elif [ "$1" = "clear" ]; then
    # YOUR CODE HERE #
    if [ "$#" -ne 1 ]; then
        echo "Usage: ./phonebook.sh clear"
        exit 1
    elif [ ! -e $PHONEBOOK_ENTRIES ] || [ ! -s $PHONEBOOK_ENTRIES ]; then
        echo "phonebook is already empty"
    else
        sed -i 'd' $PHONEBOOK_ENTRIES
    fi

else
    # YOUR CODE HERE #
    echo "Usage: ./phonebook.sh <new|list|lookup|remove|clear> <name> <number>"
fi

注意其中sed的用法(可以使用正则表达式)

sed [-hnV][-e<script>][-f<script文件>][文本文件]

• -n或--quiet或--silent 仅显示script处理后的结果。
• d ：删除，后面不接任何东西
• i ：插入， i 的后面可以接字串，而这些字串会在新的一行出现(目前的上一行)；

具体用法参见代码即可