Significance of Scripting Languages for Operating System Administration

1. INFuture2007 Significance of Scripting Languagesfor Operating System Administration Vladimir Mateljan Željka Požgaj Krunoslav Peter

2. Introduction • analysis of scripting programming languages • why they are significant for operating system (OS) administration, especially for automating administration tasks

3. OS Administration GUI Tool – pointing and clicking Command Line – writing and executing commands

4. Automation of OS Administration • sequences of OS’s shell commands – simple programming solutions – scripts • scripting languages (SLs) can be used for development of program solutions used in the automation of OS administration with a minimum code usage

5. Scripting Programming Languages • interpreted programming languages • building applications from reusable components • rapid application development • building minimalist but functional program solutions • examples: • bash – shell SL • awk – apattern scanning and text processing language

6. The Shell Language - bash • simple and expressive syntax: • command: command [switch] [argument] • statement: command [; command] • piping (sending data from one to another command): command [| command] • redirection (sending data to file): command [> file] • script: statement [statement]

7. ThePattern Scanning and Text Processing Language - awk • the syntax for invoking awk: • specifying a script on the command line: awk ‘script’ file [file] • invoking awk with a script file: awk -f script file [file] • the structure of the awk script: pattern { procedure } pattern { procedure } ... • example – counting rows in text file : $ awk '{ i++ } END { print i }' file.txt

8. Statement, Alias, and Script • statement: $ ls | grep txt | wc -l • alias: $ alias lsx='ls | wc -l' • script: #!/bin/bash echo __Text Docs__ > doc.txt ls | grep doc >> doc.txt

9. Pragmatics of SL • simple and expressive syntax • single data type – string • powerful operations – piping and redirection • example – stoping process that has string “sleep” in name: $ ps | awk '$4 ~ /sleep/ { cmd = "kill -9 " $1; print | cmd }'

10. Significance of SLs for OS Administration • scripts – tools for automating common administration tasks • additional benefits: • documenting steps of administration tasks • history (execution log)

11. Conclusion • SLs are appropriate for rapid development of program solutions used in the automation of OS administration with a minimum code usage • integration of reusable components from the framework that includes OS's shell commands