mirror of https://github.com/vinc/moros.git
175 lines
3.6 KiB
Markdown
175 lines
3.6 KiB
Markdown
# MOROS Shell
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## Config
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The shell will read `/ini/shell.sh` during initialization to setup its
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configuration.
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## Commands
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The main commands have a long name, a one-letter alias, and may have
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additional common aliases.
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**Alias** command:
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> alias d delete
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<!--
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**Append** to file:
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> a a.txt
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> append a.txt
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-->
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**Delete** file:
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> d a.txt
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> del a.txt
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> delete a.txt
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**Copy** file:
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> c a.txt b.txt
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> copy a.txt b.txt
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**Move** file:
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> m a.txt b.txt
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> move a.txt b.txt
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**Print** string:
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> p "Hi"
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> print "Hi"
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**Read** file:
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> r a.txt
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> read a.txt
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**Write** file:
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> w a.txt
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> write a.txt
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**Write** dir:
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> write /usr/alice/ # with a trailing slash to create a dir instead of a file
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**List** files in dir:
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> list /usr/alice
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When executed without arguments, this command will list the files of the
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current directory.
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**Go to** dir:
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> goto /usr/alice
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When executed without arguments, this command will print the current directory.
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## Combiners (TODO)
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The `&` and `|` symbols are used only for combiners so there's no needs to
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double them.
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**And combiner:**
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> r a.txt & r b.txt
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**Or combiners:**
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> r a.txt | r b.txt
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## Pipes (TODO)
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The pipe symbol `|` from UNIX is replaced by a thin arrow `->`, shortened to
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`>`, and the redirection symbol `>` from UNIX is replaced by a fat arrow `=>`
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(see below).
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Piping the standard output of a program to the `write` command to emulate a
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redirection for example would be `-> write` or `> w` in short.
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An additional standard stream stdnull(3) is added to simplify writing to `/dev/null`.
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Examples:
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Read file A and redirect stdout(1) to stdin(0) of write file B:
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> r a.txt > w b.txt
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> r a.txt 1>0 w b.txt # with explicit streams
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> r a.txt -> w b.txt # with thin arrow
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Read file A and redirect stderr(2) to stdin(0) of write file B:
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> r a.txt 2> w b.txt
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> r a.txt 2>0 w b.txt
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Suppress errors by redirecting stderr(2) to stdnull(3):
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> r a.txt 2>3 w b.txt
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Redirect stdout(1) to stdin(0) and stderr(2) to stdnull(3):
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> r a.txt > 2>3 w b.txt
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> r a.txt 1>0 2>3 w b.txt
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## Redirections
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Redirecting standard IO streams can be done with a fat arrow, for example the
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output of the print command can be written to a file like so:
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> print hello => /tmp/hello
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Which is more efficient than doing:
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> print hello -> write /tmp/hello
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## Variables
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- Name of the shell or the script: `$0`
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- Script arguments: `$1`, `$2`, `$3`, `$4`, ...
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- Exit code: `$?`
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- Process environment variable: `$HOME`, ...
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- Shell environment variable: `$foo`, ...
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Setting a variable in the shell environment is done with the following command:
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> set foo 42
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> set bar "Alice and Bob"
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And accessing a variable is done with the `$` operator:
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> print $foo
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42
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> print "Hello $bar"
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Hello Alice and Bob
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The process environment is copied to the shell environment when a session is
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started. By convention a process env var should be in uppercase and a shell
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env var should be lowercase.
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Unsetting a variable is done like this:
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> unset foo
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## Globbing
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MOROS Shell support filename expansion or globbing for `*` and `?` wildcard
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characters, where a pattern given in an argument of a command will be replaced
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by files matching the pattern.
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- `*` means zero or more chars except `/`
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- `?` means any char except `/`
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For example `/tmp/*.txt` will match any files with the `txt` extension inside
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`/tmp`, and `a?c.txt` will match a file named `abc.txt`.
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## Tilde Expansion
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The tilde character `~` is a shortcut to `$HOME` so `~/test` will be expanded
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to `$HOME/test` by the shell.
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