docs(skip-lines): moving the subject to the folder devops and fix readme

subjects/devops/skip-lines/README.md

@@ -7,7 +7,7 @@ Write a command line in a `skip-lines.sh` file that prints the result of a `ls -
 Example:
 
 ```console
-User-> ls -l
+$ ls -l
 drwxr-xr-x 16 User User      4096 nov 11 10:55 Desktop
 drwxr-xr-x 22 User User      4096 nov  4 10:02 Documents
 drwxr-xr-x  6 User User      4096 nov 11 10:40 Downloads
@@ -24,24 +24,29 @@ drwxr-xr-x  6 User User      4096 nov 11 10:40 Downloads
 drwxr-xr-x  2 User User      4096 set 29 10:34 Pictures
 ```
 
-**Tips:**
+### Hints
 
 Here are some Commands that can help you:
 
-- `sed`. Edit text in a scriptable manner. You can see also: awk. [For more information](https://www.gnu.org/software/sed/manual/sed.html).
+- `sed`. Edit text in a scriptable manner.
 
   - Print just a first line to stdout:
     `{{command}} | sed -n '1p'`
 
 ```console
-User-> cat file
+$ cat file
 AIX
 Solaris
 Unix
 Linux
 HPUX
-User-> sed -n '1p' file
+$ sed -n '1p' file
 AIX
 ```
 
-Use man to see how `awk` or `sed` works, they can do the job.
+> You have to use Man or Google to know more about commands flags, in order to solve this exercise!
+> Google and Man will be your friends!
+
+### References
+
+- [Sed](https://www.gnu.org/software/sed/manual/sed.html).