Linux命令(46)——read命令 1.命令简介 read命令是Shell内建命令,用于从标准输入或-u选项指定的文件描述符中读取单行,并将读取的单行根据IFS变量分割成多个字段,并将分割后的字段分别赋值给指定的变量列表var_name。第一个字段分配给第一个变量var_name1,第二个字段分配给第二个变量var_name2,依次到结束。如果指...
int file_read(struct m_inode * inode, struct file * filp, char * buf, int count) { int left,chars,nr; struct buffer_head * bh; if ((left=count)<=0) return 0; while (left) { // bmap取得该文件偏移对应的硬盘块号,然后读进来 if (nr = bmap(inode,(filp->f_pos)/BLOCK_SIZE))...
echo "选择你喜欢的操作系统" select os in Ubuntu LinuxMint Windows8 Windows10; do case $os in "Ubuntu"|"LinuxMint") echo "你喜欢 Linux" ;; "Windows8" | "Windows10") echo "你喜欢 Windows" ;; *) echo "无效输入"; break ;; # 执行完会结束 select 结构 esac echo "选择你喜欢的操作...
You can check the file’s permissions in the numeric notation using thestatcommand. stat -c '%a' filename.txtOutput754 Chmod Command Here are some examples of how to use the chmod command in numeric mode: Give the file’s owner read and write permissions and only read permissions to grou...
sed [选项参数] 'command' filename 2、选项参数说明 3、命令功能描述 4、案例实操 (0)数据准备 [jack@hadoop datas]$ touch sed.txt [jack@hadoop datas]$ vim sed.txt [jack@hadoop datas]$ cat sed.txt dong shen guan zhen wo wo lai lai ...
1) Creating file names with spaces To create files with spaces in file names, run the command as shown $ touch'firstname secondname' 1. For example, to create a file called 'linoxide docs' use the syntax below $ touch 'linoxide docs' ...
Step 6: Execute the following command in terminal to run the application. KCONFIG dotnet run Read and Edit Excel file The below code snippet illustrates how to read and edit an Excel file on Linux. C# //New instance of ExcelEngine is created //Equivalent to launching Microsoft Excel with...
return file_read(inode,file,buf,count); } printk("(Read)inode->i_mode=%06o\n\r",inode->i_mode); return -EINVAL; } 我们这里只分析普通文件的读写。所以我们继续看file_read函数。 int file_read(struct m_inode * inode, struct file * filp, char * buf, int count) ...
When you attempt to delete or modify a file on a Linux ECS, the message Read-only file system is displayed.The possible causes are as follows:A file system error caused t
The hosts file on every server contains the IP addresses and names of all servers that will participate in the availability group. The following command returns the IP address of the current server: Bash sudo ip addr show Update/etc/hosts. The following script lets you edit/etc/hostswithvi:...