How to use the command 'semver' (with examples)

The ‘semver’ command is used to parse semantic version strings. It provides various functionalities related to semantic versioning, such as checking if a version string respects the format, converting a version string, and testing if a version string matches a given range.

Use case 1: Check if a version string respects the semantic versioning format

Code:

semver 1.2

Motivation: This use case is helpful when you want to validate whether a version string adheres to the semantic versioning format.

Explanation: In this use case, the command semver is used without any additional arguments. It takes a version string (in this case, 1.2) as input and checks if it matches the semantic versioning format. If the version string is valid and matches the format, it does not produce any output. If the version string is not valid or does not match the format, it prints an error message.

Example output:

• If the version string 1.2 matches the semantic versioning format: (empty string)
• If the version string 1.2.3 does not match the semantic versioning format: “Invalid version: 1.2.3”

Use case 2: Convert a version string to the semantic versioning format

Code:

semver --coerce 1.2

Motivation: This use case can be handy when you have a version string that is not in the semantic versioning format and you want to convert it to the correct format.

Explanation: Here, the semver command is used with the --coerce option. It takes a version string (in this case, 1.2) as input and converts it to the semantic versioning format if possible. If the provided version string can be coerced to the correct format, it prints the coerced version string. If the conversion is not possible, it produces an error message.

Example output:

• If the version string 1.2 is successfully coerced to the semantic versioning format: “1.2.0”
• If the version string 1.2.a cannot be converted to the semantic versioning format: “Cannot coerce version: 1.2.a”

Use case 3: Test if a version matches a given range

Code:

semver 1.2.3 --range "^1.0"

Motivation: This use case is useful when you want to check if a specific version string (e.g., the version of a package) matches a given range of versions.

Explanation: In this use case, the semver command is used with both a version string (1.2.3) and a range (^1.0). It checks if the provided version string falls within the specified range. If the version matches the range, it does not produce any output. If the version does not match the range, it prints an error message.

Example output:

• If the version 1.2.3 matches the range ^1.0: (empty string)
• If the version 0.9.5 does not match the range ^1.0: “Invalid version: 0.9.5”

Use case 4: Test with multiple ranges

Code:

semver 1.2.3 --range ">=1.0" "<2.0"

Motivation: This use case is handy when you want to test if a version falls within multiple different ranges.

Explanation: Here, the semver command is used with a version string (1.2.3) and multiple ranges (>=1.0 and <2.0). It checks if the provided version string matches any of the specified ranges. If the version matches any of the ranges, it does not produce any output. If the version does not match any of the ranges, it prints an error message.

Example output:

• If the version 1.2.3 matches the range >=1.0 or <2.0: (empty string)
• If the version 2.5.1 does not match the ranges >=1.0 or <2.0: “Invalid version: 2.5.1”

Use case 5: Test multiple versions and return only the ones that match

Code:

semver 1.2.3 2.0.0 --range "^1.0"

Motivation: This use case is useful when you have multiple version strings and you want to filter only the ones that match a particular range.

Explanation: In this use case, the semver command is used with multiple version strings (1.2.3 and 2.0.0) and a range (^1.0). It tests each version string against the specified range. If a version string matches the range, it is returned as output. If a version string does not match the range, it is ignored.

Example output:

• If both 1.2.3 and 2.0.0 match the range ^1.0: “1.2.3”
• If only 2.0.0 matches the range ^1.0: “2.0.0”

Conclusion:

The ‘semver’ command provides powerful functionality for parsing and manipulating semantic version strings. It can be used to validate version strings, convert them to the correct format, and test if they match specific version ranges. By using the ‘semver’ command, developers can easily work with and compare different versions of software.