Shell Programming

Bash Shell Programming

A shell script is a computer program designed to be run by the Unix shell, a command line interpreter. The various dialects of shell scripts are considered to be scripting languages. Shell scripts allow several commands that would be entered manually at a command-line interface to be executed automatically, and without having to wait for a user to trigger each stage of the sequence.

A key feature of shell scripts is that the invocation of their interpreters is handled as a core operating system feature. So rather than a user's shell only being able to execute scripts in that shell's language, or a script only having its interpreter directive handled correctly if it was run from a shell (both of which were limitations in the early Bourne shell's handling of scripts), shell scripts are set up and executed by the OS itself. A modern shell script is not just on the same footing as system commands, but rather many system commands are actually shell scripts (or more generally, scripts, since some of them are not interpreted by a shell, but instead by Perl, Python, or some other language). This extends to returning exit codes like other system utilities to indicate success or failure, and allows them to be called as components of larger programs regardless of how those larger tools are implemented.

Many modern shells also supply various features usually found only in more sophisticated general-purpose programming languages, such as control-flow constructs, variables, comments, arrays, subroutines, and so on. With these sorts of features available, it is possible to write reasonably sophisticated applications as shell scripts. However, they are still limited by the fact that most shell languages have little or no support for data typing systems, classes, threading, complex math, and other common full language features, and are also generally much slower than compiled code or interpreted languages written with speed as a performance goal.

For Bash Shell Programming Tutorial click here

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Bash Shell Programming Practice

BashExercise 1
      Script 1: Add two numbers 
      Script 2: Add two numbers in various methods 
      Script 3: Declaration of variables 
      Script 4: Performing a backup with tar
      Script 5: Break or ignore specified execution
 

BashExercise 2

      Script 6: Break 2
      Script 7: Case
      Script 8: Case 2
      Script 9: Case 3
      Script 10: Esac

BashExercise 3
      Script 11: Comparision
      Script 12: Continue
      Script 13: Diff – if
      Script 14: Disk
      Script 15: Execute

BashExercise 4
      Script 16: Select and Execute
      Script 17: Firstname & Lastname
      Script 18: For Do Loop
      Script 19: For Don't Do Loop
      Script 20: For 1

BashExercise 5
      Script 21: Function 1
      Script 22: Function 2
      Script 23: Function 3
      Script 24: Function Exit
      Script 25: Function Position

BashExercise 6
      Script 26: Get Options 1
      Script 27: Get Options 2
      Script 28: If Statement 1
      Script 29: If Statement 2
      Script 30: If Statement 3

BashExercise 7
      Script 31: Leap year
      Script 32: If – Else Statement
      Script 33: Nested If-Else
      Script 34: Let
      Script 35: Mail

BashExercise 8
      Script 36: Nested For
      Script 37: Create New File
      Script 38: For
      Script 39: Check whether the two numbers are equal or not
      Script 40: Open File

BashExercise 9
      Script 41: Print Partition
      Script 42: Read1
      Script 43: Read2
      Script 44: Rev
      Script 45: SED