Harucom’s IRB runs commands for looking at files and copying them.

irb> ls
irb> cat hello.rb

These commands are Ruby scripts stored in /app. You can print one with cat, or change it with the edit command. See File I/O for details.

Looking at Files

ls — List files

irb> ls
irb> ls /app
irb> ls -l

Lists the files in the current directory. Directories are shown in a different color from files.

cat — Show the contents of a file

irb> cat hello.rb
irb> cat -n hello.rb
irb> cat file1.rb file2.rb

Prints the file as it is. -n numbers each line. Several files given at once are printed one after another.

head / tail — Show the beginning or the end

irb> head hello.rb
irb> head -n 20 hello.rb
irb> tail hello.rb

head prints the beginning of a file and tail prints the end. -n changes how many lines they show.

Moving Around

pwd — Print the current directory

irb> pwd
/

cd — Change directory

irb> cd /app
irb> cd ..
irb> cd

Changes the directory you are working in, the current directory. After moving, a plain file name passed to ls, cat, or edit refers to a file in that directory.

irb> cd /app
irb> cat ls.rb

Running cd without an argument moves to the root directory /.

Working with Files

touch — Create an empty file

irb> touch memo.txt

cp — Copy a file

irb> cp hello.rb backup.rb
irb> cp hello.rb /data/
irb> cp -f hello.rb backup.rb

When the destination is a directory, the file is copied into it under the same name. An existing file is not overwritten unless you pass -f.

mv — Move or rename a file

irb> mv old.rb new.rb
irb> mv hello.rb /data/
irb> mv -f hello.rb existing.rb

This works like cp. A destination directory receives the file under the same name.

rm — Delete files

irb> rm memo.txt
irb> rm file1.txt file2.txt

Several files can be given at once.

Harucom needs /system.rb and the files under /lib, /app, and /etc in order to boot, so these are protected. -f overrides the protection, but the board may stop booting.

Working with Directories

mkdir — Create a directory

irb> mkdir data
irb> mkdir /data/photos

rmdir — Remove an empty directory

irb> rmdir data

A directory that still holds files cannot be removed. Delete the files with rm first. As with rm, system directories need -f.

Other Commands

Command	Description
`edit`	Edit a file in the text editor
`run`	Run a Ruby script
`zoom`	Change the text size on screen New in 2.0
`picorabbit`	Show slides
`johakyu`	Live code sound and light New in 2.0

IRB itself provides a few commands.

Command	Description
`jobs`	Show whether an app is suspended New in 2.0
`fg`	Resume the suspended app New in 2.0
`exit`	Quit IRB and start it again

An app that supports it, such as picorabbit, stops and hands you back to IRB when you press Ctrl-Z while it runs. Typing fg picks it up where it left off. New in 2.0

To try out the built-in demos, see Demo Apps.