README.md

version_compare (1.0.0)

Compares semantic versions (1.0.0) versions in Bash, comparable to PHP's version_compare function.

Usage

version_compare [-hV] <version1> <version2> [<operator>]

Required arguments

• <version1>: First version number to compare.
• <version2>: Second version number to compare.

Optional arguments

• <operator>: When this argument is provided, it will test for a particular relationship. This argument is case-sensitive, values should be lowercase. Possible operators are:
  • =, ==, eq (equal)
  • >, gt (greater than)
  • >=, ge (greater than or equal)
  • <, lt (less than)
  • <=, le (less than or equal)
  • !=, <>, ne (not equal)

Return Value

There are two distinct operation modes for version_compare. It's solely based on whether or not the <operator> argument was provided:

• When <operator> IS provided, version_compare will return either a 0 or 1 exit code (no output printed to /dev/stdout) based on the result of the <operator> relationship between the versions. This is particularly useful in cases where testing versions can, historically, be quite cumbersome:

  ! version_compare ${version1} ${version2} ">" && echo "You have not met the minimum version requirements." && exit 1

  You can, of course, opt for the more traditional/verbose conditional block in that suites your fancy:

  version_compare ${version1} ${version2}
  if [ $? -gt 0 ]; then
    echo "You have not met the minimum version requirements."
    exit 1
  fi

• When <operator> is NOT provided, version_compare will output (print to /dev/stdout):

  • -1: <version1> is lower than <version2>
  • 0: <version1> and <version2> are equal"
  • 1: <version2> is lower than <version1>

  This mode is primarily only ever helpful when there is a need to determine the relationship between two versions and provide logic for all three states:

  ret=$(version_compare ${version1} ${version2})
  if [ "${ret}" == "-1" ]; then
    # Do some logic here.
  elif [ "${ret}" == "0" ]; then
    # Do some logic here.
  else
    # Do some logic here.
  fi

  While there are use cases for both modes, it's recommended that you provide an <operator> argument to reduce any logic whenever possible.

Options

• -h: Display help and exit.
• -V: Display version information and exit.