2.5 KiB
Shell Scripting
Tomo comes with a built-in lang called Shell for shell commands.
This lets you write and invoke shell commands in a more type-safe way.
user_name := ask("What's your name? ")
_ := $Shell"echo Hello $user_name"
In the above example, there is no risk of code injection, because the user-controlled string is automatically escaped when performing interpolation.
Shell Methods
func by_line(command: Shell -> Void)func execute(command: Shell -> Int32?)func run(command: Shell -> Text?)func run(command: Shell -> [Byte]?)
by_line
Description:
Run a shell command and return an iterator over its output, line-by-line.
Signature:
func by_line(command: Shell -> Void)
Parameters:
command: The command to run.
Returns:
An optional iterator over the lines of the command's output. If the command fails
to run, none will be returned.
Example:
i := 1
for line in $Shell"ping www.example.com":by_line()!:
stop if i > 5
i += 1
execute
Description:
Execute a shell command without capturing its output and return its exit status.
Signature:
func execute(command: Shell -> Int32?)
Parameters:
command: The command to execute.
Returns:
If the command exits normally, return its exit status. Otherwise return none.
Example:
>> $Shell"touch file.txt":execute()
= 0?
run
Description:
Run a shell command and return the output text from stdout.
Signature:
func run(command: Shell -> Text?)
Parameters:
command: The command to run.
Returns:
If the program fails to run (e.g. a non-existent command), return none,
otherwise return the entire standard output of the command as text. Note:
if there is a trailing newline, it will be stripped.
Example:
>> $Shell"seq 5":run()
= "1$\n2$\n3$\n4$\n5"
run_bytes
Description:
Run a shell command and return the output in raw bytes from stdout.
Signature:
func run(command: Shell -> [Byte]?)
Parameters:
command: The command to run.
Returns:
If the program fails to run (e.g. a non-existent command), return none,
otherwise return the entire standard output of the command as an array of
bytes.
Example:
>> $Shell"seq 5":run_bytes()
= [0x31, 0x0A, 0x32, 0x0A, 0x33, 0x0A, 0x34, 0x0A, 0x35, 0x0A]