How to install Composer on Debian / Ubuntu Linux

in Categories , , , , last updated August 2, 2016

I‘m trying to upgrade my Mediawiki installation and I’m getting an error that read as follows:
    Error: your composer.lock file is not up to date, run “composer update” to install newer dependencies
How do I install composer command for my PHP installation on Debian or Ubuntu Linux running LAMP or LEMP stack? How do I Install and use Composer on running Ubuntu Linux server and fix this problem for mediawiki installation and/or manage and install PHP packages and dependencies for my project?

Understanding Linux / UNIX Relative Pathname

in Categories , , , , , , , , , , , , last updated August 15, 2007

Q. Can you explain the term relative pathname under UNIX or Linux oses?

A. The relative pathnames are opposite to absolute pathname. A reative pathname does not begin with a slash ( / ). Generally you specifies location relative to your current working directory. This is most useful to short a path name. For example if your current working directory is /home/tom and if you would like to change directory to /home/tom/docs/bio you can enter command cd docs/bio instead of cd /home/tom/docs/bio .

So you can use a relative path name as a shortcut to the location of files and directories.

Relative pathname example

To refer to a file in a subdirectory of the current working directory, use the name of the subdirectory followed by a slash (/) and the name of the file. For example, to display a file called foo.text in a subdirectory called bar that is located in the current directory /home/tom, enter:
$ pwd


Now, enter the command:
$ cat bar/foo.txt

.. directory name

To refer to a file in the parent directory of the current directory, use “../” followed by the name of the file. For example,if you are in /home/tom/bar and would like to display /home/tom/file.txt use pathnane ../file.txt:
$ pwd


Now, enter the command:
$ cat ../file.txt

Home-relative pathname with tilde (~)

The tilde character (~) can be used to refer to your home directory, For example, the pathname ~/file.txt refers to a file named file.txt in your home directory /home/tom/file.txt.
$ pwd


Now, enter the command:
$ cat ~/file.txt