msh

A mini Unix shell.

Examples

To see the built in commands:

/Users/jsimpson/src/msh % help
msh, version 20210217.034931
These shell commands are defined internally. Type `help` to see this list.

cd         cd [dir]
exit       exit [status]
export     export
help       help [pattern]
pwd        pwd

Some specialty things about cd.

/Users/jsimpson/src/msh % cd
/Users/jsimpson % cd src
/Users/jsimpson/src % cd #
  /Users/jsimpson/src/msh
  /Users/jsimpson
* src
/Users/jsimpson/src % cd --
/Users/jsimpson/src/msh % cd #
* /Users/jsimpson/src/msh
  /Users/jsimpson
  src
/Users/jsimpson/src/msh % cd +
/Users/jsimpson % cd #
  /Users/jsimpson/src/msh
* /Users/jsimpson
  src
/Users/jsimpson %

A couple basic redirects (>, >&) and piping (|) work.

/Users/jsimpson % echo 1 > t
/Users/jsimpson % echo 2 >> t
/Users/jsimpson % echo 3 >> t
/Users/jsimpson % cat t
1
2
3
/Users/jsimpson % cat t | grep 3
3
/Users/jsimpson %

Development

Handy little command line that rebuilds the project on each change.

fswatch -Ee "$(basename `pwd`)/$(basename `pwd`)|$(basename `pwd`)/parser/grammar.go|$(basename `pwd`)/coverage.out|$(basename `pwd`)/.git|$(basename `pwd`)/README.md" -or . parser | xargs -n1 -I {} ./make {}

Known Issues

• You can't run msh from inside msh. It hangs.
• When you Ctrl-C a running process, it prints two instances of '^C' on the screen.
• The cd stack sometimes contains relative directories (if you cd to a relative directory.) Use cd # to see a listing of the directories.
• No glob expansion.
• No tab completion of files.
• No environment variable expansion.
• No alias support.