CMD-Mode.md

Command Line Mode

• Command-Line mode prompts us to enter:

• In Command-Line mode we can type the name of a command and then execute it by pressing <CR>.

• We can switch from Command-Line mode back to Normal mode by pressing <Esc>.

• We can use Ex commands to:

  1. read and write files :edit and :write.

  2. create tabs :tabnew or split windows :split.

  3. show the list of buffers :ls.

  4. alot more...**

  In fact, Vim has an Ex command for just about everything.

• Command-Line mode is similar to Insert mode in that most of the buttons on the keyboard simply enter a character. In Insert mode, the text goes into a buffer, whereas in Command-Line mode the text appears at the prompt.

TIP TIME

• We can insert the contents of any register at the command line using the <C-r>{register} command.
• In Command-Line mode, we can use the <Tab> key to auto-complete the name of a file or the name of a command.

Command-Line History

• Vim keeps a history of the commands we have entered in Command-Line mode, so we do not need to write all of them again.

• By default it keeps the last 20 commands we have entered, but you can change this number by changing the hisotry option, say we want vim to remember the last 200 commands that we have entered in the Command-Line mode. You can do this by writing set history=200, in your .vimrc file.

• We can use the <Up> key to go to the next command in the commands' history, and <Down> key to go to the previous command in the commands' history.

• In this way of navigation through our command's history, we do not have the all power ov vim features, like searching for a command in the history or filtering the history to show only the commands that match a pattern. Likely vim know this and introduce us to the Command-Line window.

• The Command-Line window is like a regular vim buffer where each line contains a command from our history and we can naviagte through them usine our favorite hjkl keys, and we can use search and filter to find the command we want. We can also execute the command in the current line by pressing <CR>.

• We can open the Command-Line window by pressing q: in Normal-Line mode.

Why Ex commands?

• One of the mose important features of Ex commands, is their ability to be executed across many lines at the same time.

• Many Ex commands can be given a [range] of lines to act upon. We can specify the start and end of a range with either:

  1. a line number.

  2. a mark.

  3. a pattern.

Usine Line Numbers

• if we enter a line number without any commands in Command-Line mode, vim will jump to that line.

• Examples:

  1. :1 $\to$ go to the first line in the buffer.

  2. :5 $\to$ go to the fifth line in the buffer.

  3. :$ $\to$ go to the last line in the buffer.

• If we enter a command with a line number as a [range], the command will be executed on that line only.

• Examples:

  1. :5d $\to$ delete the fifth line in the buffer.

  2. :3,8d $\to$ delete from line number 3 to line number 8 in the buffer.

  3. :1,$d or :%d $\to$ delete from the first line to the last line in the buffer.

  4. :d $\to$ delete the current line in the buffer.

• Ass you gussed from examples 2 and 3, that we can use the :{start},{end} to specify a range of lines from start to end

• As we have seen that d $\to$ delete, there are alot of other commands we can perform on text from the Command-Linemode.

• Examples:

  1. y $\to$ yank or copy the text in the buffer to the register.

  2. p $\to$ paste the text in the register to the buffer.

  3. c $\to$ change the text in the buffer.

  4. s $\to$ substitute the text in the buffer.

  5. gU $\to$ uppercase the text in the buffer.

  6. gu $\to$ lowercase the text in the buffer.

  7. > $\to$ indent the text in the buffer.

  8. < $\to$ unindent the text in the buffer.

  9. m $\to$ move the text in the buffer.

Specify a Range of Lines by Visual Selection

• We can also specify rnage of lines using visual selections.

• Try do the following:

  1. Go to visual mode by pressing :v from normal mode

  2. Select some lines using hjkl keys.

  3. Press : to go to Command-Line mode.

  4. You will see that vim has already entered the :'<,'> for you. You can think of this as the range of lines that you have selected in visual mode.

  5. Now you can enter the command you want to execute on the selected lines or the range.

Specify a Range of Lines by Patterns

• Suppose we have the following text in our buffer:

  fn main() {
    let cat = 1;
  
    if cat == 1 {
      println!("x = {}", x);
    }
  
    let dog = 2;
  
    let z = 1 + 2;
  
    println!("z = {}", z);
  }

• try to type :/cat/,/dog/d in Command-Line mode.

• this create a range of lines from the line that contains the word cat to the line that contains the word dot, and then delete them.