http://www.linux-bloggersplace.org Linux Blog | Learn Linux Tricks Thu, 12 Jun 2008 11:42:41 +0000 http://backend.userland.com/rss092 en The for loop is used to process a list of items. The list can be supplied in the script. It could also be taken from the script arguments, from a file, or from the output of a command. The syntax of the for construct is as follows: for list do command_list done All the commands ... http://www.linux-bloggersplace.org/2007/12/07/the-for-loop/ In common with most programming languages, Unix shell scripting caters for instructions to be carried out repetitively. The while loop will repeat a list of commands as long as a given condition is true. All of the conditional statements used in the if...fi construct can be used here, including string ... http://www.linux-bloggersplace.org/2007/12/07/the-while-loop/ The set command can be used to store a new set of values in the script arguments ($1, $2 etc.). This can be useful for separating the output from a command into separate components that can be worked with individually. The set command requires a string of arguments separated ... http://www.linux-bloggersplace.org/2007/12/04/using-the-set-command/ Scripts should run with as little user intervention as possible. There are several reasons for this. Firstly, the whole point of having a script is to reduce the amount of typing needed to run a job. Secondly, scripts should be able to be run by users with little or no ... http://www.linux-bloggersplace.org/2007/12/04/providing-input-to-commands-within-a-script/ In a previous article, we looked at making commands within the script execute only if a given condition is true, using the if....else...fi construct. However, this construct can often become very clumsy when there are several possible conditions to be accounted for. Take the menu script example below: clear echo User Menu ... http://www.linux-bloggersplace.org/2007/12/04/the-case-command/ Normally, when you run a command from a script, the output from the command goes to the standard output: usually the user’s terminal. However, you may want to do further work with the output from the command, or use it to make decisions within the script. Lets take a simple example. ... http://www.linux-bloggersplace.org/2007/11/30/command-substitution/ Certain characters have special meaning to the shell. These are known as metacharacters. They are listed below. Pattern Matching: This set of metacharacters is used in pattern matching, also known as wild cards. *    Match zero or more characters ?    match exactly one character []   Match a list or range of characters eg [AB], [A-N] [!]  Match anything except the ... http://www.linux-bloggersplace.org/2007/11/30/metacharacters/ The term RAID stands for Redundant Array of Independent Disks. RAID technology allows you to group together the storage capacities of two or more disks, and manage them as a single storage unit. Users are unaware that this array is not a single disk. A RAID array is known as ... http://www.linux-bloggersplace.org/2007/11/17/1understanding-raid/ In a large installation, it is sometimes difficult to keep control of user activities. Some user programs can use excessive resources, to the detriment of other users. This is particularly true in universities and colleges, where student’s activities can leave few resources for programs run by staff. Also some services ... http://www.linux-bloggersplace.org/2007/11/11/setting-user-limits/ In another article, we briefly looked at the find command, which searches for specified files. We will now look at more uses of this very powerful command. It can be used to search for files using various criteria, including name, owner and time last changed. Additionally, it can execute a command ... http://www.linux-bloggersplace.org/2007/11/08/further-uses-of-the-find-command/