1.将指定内容写入文件

echo "hello world" > file.txt

echo "hello world" >> file.txt //上面那个是覆盖,这个是追加

2.读取文件内容

写法一：----------------------------------------------------------------------------#!/bin/bashwhile read linedo    echo $linedone < file(待读取的文件)----------------------------------------------------------------------------写法二：----------------------------------------------------------------------------#!/bin/bashcat file(待读取的文件) | while read linedo    echo $linedone----------------------------------------------------------------------------写法三：----------------------------------------------------------------------------for line in `cat file(待读取的文件)`do    echo $linedone----------------------------------------------------------------------------说明：for逐行读和while逐行读是有区别的,如:$ cat fileaaaabbbbcccc dddd$ cat file | while read line; do echo $line; doneaaaabbbbcccc dddd$ for line in $(

 3.杀死某个程序的所有进程,grep后面添加杀死的条件

kill -9 `ps -ef | grep process_name | grep -v "grep" | awk '{print $2}'`