andsh

My blog post: Building a Shell

A tiny shell in C with pipes, cd, env var expansion, history, and tab completion.

./andsh
andsh$ cd /
andsh$ pwd
/
andsh$ echo $HOME
/Users/andrew
andsh$ nosuchcommand
nosuchcommand: No such file or directory
andsh$ echo $?
127
andsh$ printf abc\n | tr a-z A-Z | rev
CBA
andsh$ ec<Tab> hello
andsh$ echo hello
hello
andsh$ <Up>
andsh$ echo hello
hello
andsh$ ^D

I'm building it up a piece at a time, mostly to learn more about how shells work under the hood and to have something to write about.

build
make
run
./andsh

Non-goal: try to be bash or zsh.

Tests

Note: I've only tested on macOS.

./test.sh
ok - build
ok - echo
ok - cd
ok - cd home
ok - env var
nosuchcommand: No such file or directory
ok - last status
ok - pipe
ok - completion
ok - ctrl-d exits
ok - history
ok - left right

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