Where can I find software on CS machines?

On the CS linux machines, the installed software comes from either CentOS’s repositories or is built from source. Packages from repositories get installed under standard system locations (like /bin, /usr/bin, etc).

Software built from source is installed under /usr/local/<sw-name>

How do I know if a system binary is installed?

To find look for a binary use the command:

which <binary-name>

For example, if you would like know if the binary npm is installed:

which npm

If the binary is available, the above command would show the path in the output:


And if it is not available, the command would say that it’s not available.

which foo

which: no foo in (/bin:/usr/bin:/sbin:/usr/sbin:/usr/local/bin)

How do I know if a system package is installed?

If you know the exact name of the package, then you can query if it is installed by the command:

rpm -q <package-name>

The above command returns the package version, if the package is installed.

For instance, to check if the package “gcc” is available:

rpm -q gcc

If you do not know the exact package name, use the following command to search:

rpm -qa | grep <keywords>

This would provide a list of installed packages whose name matches the keywords supplied.

How do I know if a package built from source is available?

A complete list of software built from source is provided this web page.

You can also browse the /usr/local directory via the ls command:

ls -l /usr/local/

Software is installed under sub-directories named after the software.