Unix Tutorial Eight

8.1 UNIX Variables                   Variables are a way of passing information from the shell to programs when you run them. Programs look "in the environment" for particular variables and if they are found will use the values stored. Some are set by the system, others by you, yet others by the shell, or any program that loads another program.                    Standard UNIX variables are split into two categories, environment variables and shell variables. In broad terms, shell variables apply only to the current instance of the shell and are used...

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Unix Tutorial Seven

7.1 Compiling UNIX software packages                We have many public domain and commercial software packages installed on our systems, which are available to all users. However, students are allowed to download and install small software packages in their own home directory, software usually only useful to them personally. There are a number of steps needed to install the software. Locate and download the source code (which is usually compressed) Unpack the source code Compile the code Install the resulting executable Set paths to the installation directory Of the above steps, probably the most difficult...

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Unix Tutorial Six

Other useful UNIX commands quota                All students are allocated a certain amount of disk space on the file system for their personal files, usually about 100Mb. If you go over your quota, you are given 7 days to remove excess files. To check your current quota and how much of it you have used, type % quota -v df                 The df command reports on the space left on the file system. For example, to find out how much space is left on the fileserver, type % df . du                 The du command outputs the...

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Unix Tutorial Five

5.1 File system security (access rights)            In your unixstuff directory, type % ls -l (l for long listing!)            You will see that you now get lots of details about the contents of your directory, similar to the example below.             Each file (and directory) has associated access rights, which may be found by typing ls -l. Also, ls -lg gives additional information as to which group owns the file (beng95 in the following example): -rwxrw-r-- 1 ee51ab beng95 2450 Sept29 11:52 file1 In the left-hand column is a 10 symbol string consisting...

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