#Take the filename from the command-line argument filename=$1 #Check whether the argument is missing or not if["$filename"!=""];then #Check whether the file exists or not using the -f operator if[[-f"$filename"]];then echo"File exists." ...
# 强制退出i# insertesc# to command mode:w# save ,有:的命令叫ex command# moveh, j, k, l ctrl-f/b numberG gg# 第一个字符G last line of the file0(zero) 行首 ^ To the first non-whitespace character on the current line.$endof current line w beginning ofnextwordorpunctuation W ig...
root@raspberry:~# ddif=/home/user/Downloads/debian.iso of=/dev/sdb1 bs=512M; sync 注意:在上面的例子中,usb设备就是sdb1(你应该使用lsblk命令验证它,否则你会重写你的磁盘或者系统),请慎重使用磁盘的名,切忌。 dd 命令在执行中会根据文件的大小和类型 以及 usb设备的读写速度,消耗几秒到几分钟不等。
# 基础使用 ubuntu@VM-8-8-ubuntu:/tmp$ cheat cp # To copy a file: cp ~/Desktop/foo.txt ~/Downloads/foo.txt # To copy a directory: cp -r ~/Desktop/cruise_pics/ ~/Pictures/ # To create a copy but ask to overwrite if the destination file already exists: cp -i ~/Desktop/foo....
(default 10) --checkpoint-action=ACTION execute ACTION on each checkpoint --full-time print file time to its full resolution --index-file=FILE send verbose output to FILE -l, --check-links print a message if not all links are dumped --no-quote-chars=STRING disable quoting for characters...
You can also send the standard error to the same place as stdout with the >& notation. For example, to send both standard output and standard error to the file named f, try this command: 你也可以使用 >& 符号将标准错误发送到与stdout相同的位置。例如,要将标准输出和标准错误都发送到名为f的...
例如,要将file1重命名为file2,输入以下命令: mv file1 file2 您还可以使用mv将多个文件移动到不同的目录: mv file1 ... fileN dir 2.3.4 touch The touch command creates a file. If the file already exists, touch does not change it, but it does update the file’s modification time stamp pr...
Typical free command output. The output is displayed in bytes. $ free total used free shared buffers cached Mem: 3566408 1580220 1986188 0 203988 902960 -/+ buffers/cache: 473272 3093136 Swap: 4000176 0 4000176 If you want to quickly check how many GB of RAM your system has use the -g...
bindkey - Binds keys to an edit command. All bindings will be shown if no options is specified. bison - Generates a parser program for specified grammar file. bltin - Runs the internal command in the shell. break - Exits from a for, foreach, while, select or until loop. builtin - ...
touch /home/user/newfile.txtThe above command creates a new empty file called “newfile.txt” in the user’s /home/user directory. If newfile.txt already exists, it will update the access and modification times on the file instead.