envsubst

README

envsubst

envsubst is a Go package for expanding variables in a string using ${var} syntax. Includes support for bash string replacement functions.

Documentation

Documentation can be found on GoDoc.

Supported Functions

• ${var^}
• ${var^^}
• ${var,}
• ${var,,}
• ${var:position}
• ${var:position:length}
• ${var#substring}
• ${var##substring}
• ${var%substring}
• ${var%%substring}
• ${var/substring/replacement}
• ${var//substring/replacement}
• ${var/#substring/replacement}
• ${var/%substring/replacement}
• ${#var}
• ${var=default}
• ${var:=default}
• ${var:-default}

Unsupported Functions

• ${var-default}

• ${var+default}

• ${var:?default}

• ${var:+default}

Documentation

Index

• func Eval(s string, mapping func(string) string) (string, error)
• func EvalEnv(s string) (string, error)
• type Template
  • func Parse(s string) (t *Template, err error)
  • func ParseFile(path string) (*Template, error)
  • func (t *Template) Execute(mapping func(string) string) (str string, err error)

Functions

func Eval

func Eval(s string, mapping func(string) string) (string, error)

Eval replaces ${var} in the string based on the mapping function.

func EvalEnv

func EvalEnv(s string) (string, error)

EvalEnv replaces ${var} in the string according to the values of the current environment variables. References to undefined variables are replaced by the empty string.

Types

type Template

type Template struct {
	// contains filtered or unexported fields
}

Template is the representation of a parsed shell format string.

func Parse

func Parse(s string) (t *Template, err error)

Parse creates a new shell format template and parses the template definition from string s.

func ParseFile

func ParseFile(path string) (*Template, error)

ParseFile creates a new shell format template and parses the template definition from the named file.

func (*Template) Execute

func (t *Template) Execute(mapping func(string) string) (str string, err error)

Execute applies a parsed template to the specified data mapping.