Create and edit file

This chapter shows you how to create simple files under Beckhoff RT Linux®, set their access rights, edit content with the command line editor nano and execute scripts.

Create file

1. Create a new file called example.txt in your home directory with the touch command:

touch ~/example.txt

2. Check that the file has been created by listing the contents of your home directory:

ls -l ~

3. Set the permissions for the file with chmod. Take a look at the manpage: https://manpages.debian.org/chmod (or man chmod on your system) and select the appropriate option.

chmod [OPTION] ~/example.txt

4. Check whether the authorizations have been set correctly by listing the contents of your home directory again:

ls -l ~

Edit file

5. Now that you have created a file, we will edit it using the nano text editor. Nano is a command line text editor that is controlled via the keyboard.

nano ~/example.txt

6. This will open the file example.txt in the nano editor. Please copy the following text and paste it into the file:

#!/bin/bash

echo "My first script"

if test $# -eq 0; then
    echo "No options has passed to my command"
    exit 0
fi

echo "These are the passed options:"

i=1
for c in $@; do
    echo "$i: $c"
    i=$(($i+1))
done

7. To save the file and exit nano, press CTRL + X, then Y to confirm the save and then ENTER to write the changes.

8. Check whether the file has been saved correctly by displaying its contents with the command cat:

cat ~/example.txt

9. You have written your first script. Execute the script with the command bash:

bash example.txt --param1 a -f argument

10. Instead of bash, you can also make the script executable and run it directly. To do this, set the execution authorization with chmod or the owner of the file:

chmod u+x ~/example.txt

11. Now you can execute the script directly:

~/example.txt --param1 a -f argument