Updating path in bash shell


Furthermore, many sysadmins and DBAs find it necessary or convenient to automate tasks related to their work.The installation of software, monitoring of system resources, and management of systems involve repetitive and error-prone tasks are better addressed through automated processes than manual procedures.

Now more than ever, DBAs need to have knowledge of and experience on this platform to best administer the systems under their watch.A Unix shell provides an interface that lets the user interact with the operating system by running commands.But a shell is also a fairly rich programming language: there are constructs for flow control, alternation, looping, conditionals, basic mathematical operations, named functions, string variables, and two-way communication between the shell and the commands it invokes.There is a traditional division of responsibilities between sysadmins and DBAs.However, in practice, the distinction is not always clear.There are other variables too, like PS2, PS3, and PS4.Bash displays the primary prompt PS1 when it's ready to read a command. By default most, Linux distro displays hostname and current working directory.But only a few may be knowing about customizing the Bash prompt.Bash processing is much like a shell pipeline: after being read from the terminal or a script, data is passed through a number of stages, transformed at each step, until the shell finally executes a command and collects its return status.This chapter will explore bash's major components: input processing, parsing, the various word expansions and other command processing, and command execution, from the pipeline perspective.

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