Files

• bash-array-comparison.sh
  • How to compare two arrays in Bash
• bash-array-usage.sh
  • Examples of working with Bash arrays
• bash-checks-comparisons.sh
• • Various comparisons and equality checks
• bash-getopts.sh
  • Uses Bash cases to add switch functionality to scripts
• bash-if-while-for-functions.sh
  • Examples of Bash if/elif/else, while, and for statements in both functions and one-liners
• bash-yesno.sh
  • Simple Yes/No comparison check, accounting for case

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Variable	Description
$0	name of current script
$1 - $9	first nine script arguments
$#	count of arguments
$@	all arguments
$?	exit status of most recent process
$$	process ID of running script
$USER	current username
$HOSTNAME	machine hostname
$RANDOM	a random number
$LINENO	current line number

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Operator	True If
!EXPRESSION	The EXPRESSION is false.
-n STRING	STRING length is greater than zero
-z STRING	The length of STRING is zero (empty)
STRING1 != STRING2	STRING1 is not equal to STRING2
STRING1 = STRING2	STRING1 is equal to STRING2
INTEGER1 -eq INTEGER2	INTEGER1 is equal to INTEGER2
INTEGER1 -ne INTEGER2	INTEGER1 is not equal to INTEGER2
INTEGER1 -gt INTEGER2	INTEGER1 is greater than INTEGER2
INTEGER1 -lt INTEGER2	INTEGER1 is less than INTEGER2
INTEGER1 -ge INTEGER2	INTEGER1 is greater than or equal to INTEGER 2
INTEGER1 -le INTEGER2	INTEGER1 is less than or equal to INTEGER 2
-d FILE	FILE exists and is a directory
-e FILE	FILE exists
-r FILE	FILE exists and has read permission
-s FILE	FILE exists and it is not empty
-w FILE	FILE exists and has write permission
-x FILE	FILE exists and has execute permission