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<>Linux中清空文件的方法
平时工作过程中,经常会遇到需要清空linux中某个日志文件的方法,下面总结一下几个常用的方法:
以下待清空的文件名统一使用 test.txt 表示。
<>方法1:vi 中使用 %d
1- 输入 vi test.txt 回车
2- 按esc键 然后按shift+:号进入命令行模式
3- 命令行中输入 %d 回车
4- 重新进入命令行模式,输入:wq保存并退出
5- 再次查看文件大小,此时为0
<>方法2:重定向
重定向包含多重方法,但道理一样
1- cat /dev/null>test.txt
/dev/null文件是一个特殊的文件,它将清空重定向到它的输出,而它的输入是个空白文件,因此,可以使用cat命令查看/dev/null文件的内容,然后重定向输出到指定文件,达到清空的目的。
2- >test.txt
直接使用>test.txt来清空test.txt文件
3- : >test.txt
直接使用: >test.txt来清空test.txt文件
4- true >test.txt
直接使用 true >test.txt 来清空test.txt文件
<>方法3:使用echo来清空文件
次方法同样有多种方式:
1- echo " ">test.txt
次方法清空后,会在文件中添加一个空字符
2- echo >test.txt
<>方法4:truncate
此方法可以将文件压缩到指定大小,如果想将文件清空,则 -s后的参数值给定为0
truncate -s 0 test.txt