CRLF vs LF

These days I am coding a Linux shell running for AZcopy, since my laptop is running windows, so I switch between two operations systems. The strange problem came soon:

  1. ./azCopyToAzure.sh: line 7: $’\r’: command not found
  2. source ./config.cfg can not found
  3. when I was using echo ${log_dir}!!!, the result is !!!XXX, basically, the !!! will come to the beginning and overwrite ${log_dir}

After wasting almost two days, I found the problem. It caused by difference between end of sequence in windows and Linux. Here is from wiki:

The term CRLF refers to Carriage Return (ASCII 13, \r) Line Feed (ASCII 10, \n). They’re used to note the termination of a line, however, dealt with differently in today’s popular Operating Systems. For example: in Windows both a CR and LF are required to note the end of a line, whereas in Linux/UNIX a LF is only required. In the HTTP protocol, the CR-LF sequence is always used to terminate a line.

https://www.owasp.org/index.php/CRLF_Injection

In vs code , we have to change this setting at the bottom of right side.

I thought there should not be many person developing bash on windows, but if you are, hope this can solve some of your problems.

Inside the Linux kernel

cite from: http://turnoff.us/geek/inside-the-linux-kernel/

enter image description here
1. The foundation is a file system. PID 421 is accessing files, while a watch dog is monitoring the whole file system.
2. On the first floor, we can find a process table, the “mom” is PID 1. PID 1341(apache http) for port 80, PID 52 for ssh(22), and nobody for expired FTP(21). Also there are some others, like wine, pipes, cron and a hacker closing to the watch dog. PID in this floor can go upstairs to IO or down stairs to access file system.
3. Go upstairs, two pids are responsible to input and output(tty)

Windows + Linux = WSL

I still remembered the song “pineapple”, the singer is a wired middle age man, looks like this: Today, what I wanna talk about is similar to “pineapple”. It’s called “WSL”.

what is WSL?

WSL is an abbr for windows subsystem for linux, where you can run linux on windows like an app.

How does it work?

very simple!

  1. run windows store , find ubuntu and install it.
  2. check the wsl option in turn windows feature on or off
    • you need to restart you computer after check it.
  3. run ubuntu as your application, all commands are same.

Where is GUI?

Sorry, by default, it is only a kernal system. So, basicly you have to run with commands. But there is a workaround: Xming. You can find detail here . I only tried two steps: install ‘Xming’ and setting display export DISPLAY=:0 . Then I did successfully run Geany with GUI! Don’t tell me you don’t know how to run app on consoler.

Existing Problem

I tried install program by sanpd, but it awalys showed me error message.

Who can try it

If you like both Linux and windows, WSL gives you a opportunity to waive the dual booting problem. You can aslo access windows drivers under /mnt/.

Have fun!