Less and more command in Ubuntu

Task:

1. Pagination
2. Tab Completion
3. Command History
4. Dot Files

Let's log into our server.

1. Pagination

Let's open the man page for more man more

$ more - file perusal filter for crt viewing

more is used to display text onto the screen page by page. aka Pagination.

Now let us use the more command

$ more /var/log/auth.log

This shows pages of the auth.log you can see more at the bottom, and it shows the percentage of the file we are seeing. You can use enter to go down one line at a time. You can use space to go down one page at a time, If you need help you can enter h for help.

h - help

This will give you some other ways to use more.

Another command is less.

$ less /var/log/auth.log

The difference with less is that you can use the arrow keys to move one line at a time.

You can go back to the beginning of the file by hitting the lower-case g.

g -BOF

or you can go to the end of the file by hitting shift + g

G - EOF

You can perform a search by using the /

/ - search

/sudo

You can hit n to go to the next result

n- next

If you need to go back hit shift + N

N - previous

If you need help you can enter h for help.

h - help

As you see less has a lot more features than more. You can search, jump and change the file.

To quite hit q.

2. Tab Completion

You can save time when typing commands by using tab completion.

$ less /var/log/auth.log

If you use a tab and you get a beep from the command line or it does not respond immediately you can hit the tab a second time and it will give you a menu of options.

For a command-line this short it doesn't seem to make a big difference. But if you have a lot of parameters to give or if you are in a time crunch because the server is not performing as it should.

Also if something is not in the system, it will not show and will give you two beeps. Letting you know you are doing something wrong.

3. Command History

Let's say you have been doing a lot of work on your server. Completing a project, and you want to go back and document what all was done.

You can view your command history.

$ history

You can also re-run a command from your history by typing ( ! ) and the number beside it.

$ !133

This will execute the command again.

You can also limit the command history you see by specifying the number of lines.

$ history 10

Let's say you need just the last command from your history.

$ !-1 or $ !! as you have seen me do in previous videos.

Let's say you need to re-run the last sudo command.

$ !sudo

Your command line history can also be found in a file.

$ less ~/.bash_history

It's the same thing only difference is that it is not interactive like the comment history.

4. Dot Files

I mentioned in an earlier video that hidden files start with a (.) that is why they are called "dot files".

You can use ls -a to see hidden files.

$ ls -a

Most of these are the personal setting for your home directory.

So if you want to change your system, move to a different distro, if you want to reconfigure your prompt, or change your text editor. This information is all stored in dot files.

Let’s view the .bashrc file $ less ~/.bashrc

We are using less to prompt the contents on the screen for us. This is a little hard to read. Let's try to use our text editor. You should have vi installed by default with ubunt. Another good editor is nano

$ vi ~/.bashrc

As you can see this is a better view and different information is highlighted so you can read it easier.

You can see information about History, how big is history?

HISTSIZE=1000 HISTFILESIZE=2000

You can also the configuration for the prompt here.

PS1=

To exit VI editor without saving changes:

:q!

To exit Vi editor saving changes:

esc shift+ZZ

As you can see editing configuration files is something you need to learn as a system administrator.

See everyone next week. Be sure to hit the like button, click subscribe, and comment below any videos you would like for me to make. ... https://www.youtube.com/watch?v=MZXnEd2pCa8