Commenting Multiple Lines

  1. First, press ESC.
  2. Go to the line from which you want to start commenting. …
  3. use the down arrow to select multiple lines that you want to comment.
  4. Now, press SHIFT + I to enable insert mode.
  5. Press # and it will add a comment to the first line.

Single-line comments:

A single-line comment starts with hashtag symbol with no white spaces (#) and lasts till the end of the line. If the comment exceeds one line then put a hashtag on the next line and continue the comment. The shell script is commented out prefixing # character for single-line comment.

Bash comments can only be done as single-line comment using the hash character # . Every line or word starting by the # sign cause all the following content to be ignored by the bash shell. This is the only way to do a bash comment and ensure text or code is absolutely not evaluated in Bash.

To create a single line comment in JavaScript, you place two slashes “//” in front of the code or text you wish to have the JavaScript interpreter ignore. When you place these two slashes, all text to the right of them will be ignored, until the next line.

#!/bin/sh # This is a comment! … If you’re using GNU/Linux, /bin/sh is normally a symbolic link to bash (or, more recently, dash). The second line begins with a special symbol: # . This marks the line as a comment, and it is ignored completely by the shell.

In Shell or Bash shell, we can comment on multiple lines using << and name of comment. we start a comment block with << and name anything to the block and wherever we want to stop the comment, we will simply type the name of the comment.

The keyboard shortcut to comment multiple in Windows is shift + alt + A .

How do I run a shell script?

Steps to write and execute a script

  1. Open the terminal. Go to the directory where you want to create your script.
  2. Create a file with . sh extension.
  3. Write the script in the file using an editor.
  4. Make the script executable with command chmod +x <fileName>.
  5. Run the script using ./<fileName>.

To comment out blocks in vim:

  1. press Esc (to leave editing or other mode)
  2. hit ctrl + v (visual block mode)
  3. use the ↑ / ↓ arrow keys to select lines you want (it won’t highlight everything – it’s OK!)
  4. Shift + i (capital I)
  5. insert the text you want, e.g. %
  6. press Esc Esc.

Unlike most of the programming languages, Bash doesn’t support multiline comments. The simplest way to write multiline comments in Bash is to add single comments one after another: # This is the first line.

Writing comments in React JSX

To write comments in JSX, you need to use JavaScript’s forward-slash and asterisk syntax, enclosed inside a curly brace {/* comment here */} .

A comment starts with a double hyphen ( — ) anywhere outside a string. They run until the end of the line. You can comment out a full block of code by surrounding it with –[[ and –]] . To uncomment the same block, simply add another hyphen to the first enclosure, as in —[[ .

In Vim:

  1. go to first line of block you want to comment.
  2. shift-V (enter visual mode), up down highlight lines in block.
  3. execute the following on selection :s/^/#/
  4. the command will look like this: :'<,’>s/^/#
  5. hit enter.

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