README
¶
gsh - An alternative to write shell scripts
This is an alternative to write shell scripts.
Yes, now you can write shell script in XGo. It supports all shell commands.
Usage
First, let's create a file named example.gsh and write the following code:
mkdir "testgsh"
You don't need a go.mod file, just enter xgo run ./example.gsh directly to run.
It's strange to you that the file extension of XGo source is not .xgo but .gsh. It is only because XGo register .gsh as a builtin classfile.
We can change example.gsh more complicated:
type file struct {
name string
fsize int
}
mkdir! "testgsh"
mkdir "testgsh2"
lastErr!
mkdir "testgsh3"
if lastErr != nil {
panic lastErr
}
capout => { ls }
echo output.fields
capout => { ls "-l" }
files := [file{flds[8], flds[4].int!} for e <- output.split("\n") if flds := e.fields; flds.len > 2]
echo files
rmdir "testgsh", "testgsh2", "testgsh3"
Execute shell commands
There are many ways to execute shell commands. The simplest way is:
mkdir "testgsh"
It is equivalent to:
exec "mkdir", "testgsh"
or:
exec "mkdir testgsh"
If a shell command is a Go/XGo language keyword (eg. go), or the command is a relative or absolute path, you can only execute it in the latter two ways:
exec "go", "version"
exec "./test.sh"
exec "/usr/bin/env xgo run ."
You can also specify environment variables to run:
exec "GOOS=linux GOARCH=amd64 go install ."
Retrieve environment variables
You can get the value of an environment variable through ${XXX} or $XXX. For example:
echo ${HOME}
ls $HOME
You can also use exec command through $XXX:
exec "ls $HOME"
Check last error
If we want to ensure mkdir successfully, there are three ways:
The simplest way is:
mkdir! "testsh" # will panic if mkdir failed
The second way is:
mkdir "testsh"
lastErr!
Yes, gsh provides lastErr to check last error.
The third way is:
mkdir "testsh"
if lastErr != nil {
panic lastErr
}
This is the most familiar way to Go developers.
Capture output of commands
And, gsh provides a way to capture output of commands:
capout => {
...
}
Similar to lastErr, the captured output result is saved to output.
For example:
capout => { ls "-l" }
echo output
Here is a possible output:
total 72
-rw-r--r-- 1 xushiwei staff 11357 Jun 19 00:20 LICENSE
-rw-r--r-- 1 xushiwei staff 127 Jun 19 10:00 README.md
-rw-r--r-- 1 xushiwei staff 365 Jun 19 00:25 example.gsh
-rw-r--r-- 1 xushiwei staff 126 Jun 19 09:33 go.mod
-rw-r--r-- 1 xushiwei staff 165 Jun 19 09:33 go.sum
-rw-r--r-- 1 xushiwei staff 1938 Jun 19 10:00 xgo_autogen.go
We can use XGo powerful built-in data processing capabilities to process captured output:
type file struct {
name string
fsize int
}
files := [file{flds[8], flds[4].int!} for e <- output.split("\n") if flds := e.fields; flds.len > 2]
In this example, we split output by "\n", and for each entry e, split it by spaces (e.fields) and save into flds. Condition flds.len > 2 is to remove special line of output:
total 72
At last, pick file name and size of all selected entries and save into files.
Documentation
¶
Index ¶
- Constants
- func Getenv(env []string, name string) string
- func InitApp(app *App)
- func Setenv__0(ret []string, env map[string]string) []string
- func Setenv__1(ret []string, name, val string) []string
- func Setenv__2(ret []string, env []string) []string
- func XGot_App_Main(a interface{ ... })
- type App
- func (p *App) Capout(doSth func()) (string, error)
- func (p *App) Exec__0(env map[string]string, name string, args ...string) error
- func (p *App) Exec__1(cmdline string) error
- func (p *App) Exec__2(name string, args ...string) error
- func (p *App) ExitCode() int
- func (p *App) LastErr() error
- func (p *App) Output() string
- func (p *App) XGo_Env(key string) string
- func (p *App) XGo_Exec(name string, args ...string) error
- type OS
Constants ¶
const (
XGoPackage = true
)
Variables ¶
This section is empty.
Functions ¶
func Getenv ¶ added in v1.13.9
Getenv retrieves the value of the environment variable named by the key. It returns the value, which will be empty if the variable is not present. To distinguish between an empty value and an unset value, use LookupEnv.
func InitApp ¶ added in v1.15.2
func InitApp(app *App)
InitApp initializes an App instance. It is provided so that an App instance embedded in a struct can be initialized from another package.
func XGot_App_Main ¶ added in v1.16.0
func XGot_App_Main(a interface{ initApp() })
XGot_App_Main is main entry of this classfile.
Types ¶
type App ¶
type App struct {
// contains filtered or unexported fields
}
App is project class of this classfile.
func (*App) Exec__1 ¶ added in v1.13.9
Exec executes a shell command line with $env variables support.
- exec "XGO_GOCMD=tinygo xgo run ."
- exec "ls -l $HOME"
func (*App) ExitCode ¶ added in v1.13.9
ExitCode returns exit code of last command execution. Bash-scripting exit codes: 1: Catchall for general errors 2: Misuse of shell builtins (according to Bash documentation) 126: Command invoked cannot execute 127: Command not found 128+n: Fatal error signal "n" 254: Unknown error(*)
type OS ¶ added in v1.13.9
type OS interface {
// Environ returns a copy of strings representing the environment,
// in the form "key=value".
Environ() []string
// ExpandEnv replaces ${var} or $var in the string according to the values
// of the current environment variables. References to undefined
// variables are replaced by the empty string.
ExpandEnv(s string) string
// Getenv retrieves the value of the environment variable named by the key.
// It returns the value, which will be empty if the variable is not present.
// To distinguish between an empty value and an unset value, use LookupEnv.
Getenv(key string) string
// Run starts the specified command and waits for it to complete.
Run(c *exec.Cmd) error
}
var Sys OS = defaultOS{}
Source Files