tomhrr/cosh

cosh

cosh is a concatenative command-line shell.

• Why?
• Install
  • Dependencies
  • Supported systems
  • Building
  • Running
• Examples
• Documentation
• Licence

Why?

Basic shell operations like ls, ps, stat, and so on are implemented as functions that return first-class values, as opposed to relying on executables that return text streams. This makes working with the results simpler:

• Find files matching a path, and search them for data:

  • sh:     find . -iname '*test*' -print0 | xargs -0 grep data
  • cosh: lsr; [test m] grep; [f<; [data m] grep] map

• Find the total size of all files in the current directory:

  • sh:     ls | xargs stat -c %s | awk '{s+=$1} END {print s}' -
  • cosh: ls; [is-dir; not] grep; [stat; size get] map; sum

A small set of versatile primitives means that less needs to be remembered when compared with typical shells (see e.g. the various flags for cut(1)), though some commands may be longer as a result:

• Get the second and third columns from each row of a CSV file:

  • sh:     cut -d, -f2,3 test-data/csv
  • cosh: test-data/csv f<; [chomp; , split; (1 2) get] map

• Sort files by modification time:

  • sh:     ls -tr
  • cosh: ls; [[stat; mtime get] 2 apply; <=>] sortp

Arithmetical operators and XML/JSON/CSV encoding/decoding functions reduce the number of times that it becomes necessary to use a more full-featured programming language or a third-party executable:

• Increment floating-point numbers in file:

  • sh:     sed 's/$/+10/' nums | bc
  • cosh: nums f<; [chomp; 10 +] map;

• Get the first value from the "zxcv" array member of a JSON file:

  • sh:     jq .zxcv[0] test-data/json2
  • cosh: test-data/json2 f<; from-json; zxcv get; 0 get

It also integrates with external executable calls, where that is necessary:

• Print certificate data:
  • bash: for i in `find . -iname '*.pem'`; do openssl x509 -in $i -text -noout; done
  • cosh: lsr; [pem$ m] grep; [{openssl x509 -in {} -text -noout}] map;

See the full documentation for more details.

Install

Dependencies

• Rust

Supported systems

This has been tested on Linux (Debian 12), but should work on any Linux/macOS/BSD system where Rust can be built.

Building

make
make test
sudo make install

Apart from the core cosh executable, this will also install a compiled library of core functions (rt.chc).

Running

user@host:/$ cosh
/$ hello println;
hello

Examples

Each example starts from the repository clone directory.

List files in a specified directory:

cosh$ test-data ls
v[gen (
    0: test-data/json-bigint
    1: test-data/json2
    2: test-data/json1
    3: test-data/readfile
    4: test-data/csv
    5: test-data/split
)]
cosh$

Sort files alphabetically in a specified directory:

cosh$ test-data ls; sort
(
    0: test-data/csv
    1: test-data/json-bigint
    2: test-data/json1
    3: test-data/json2
    4: test-data/readfile
    5: test-data/split
)
cosh$

An external command can be run by prefixing the command with a space:

cosh$  vim test-data/csv
...

Read a file into memory:

cosh$ test-data/csv f<;
v[gen (
    0: "1,2,3,4\n"
    1: "5,6,7,8\n"
    2: "9,10,11,12\n"
)]
cosh$

For each line of a CSV file, remove the newline and split on commas:

cosh$ test-data/csv f<; [chomp; , split] map;
v[gen (
    0: (
        0: 1
        1: 2
        2: 3
        3: 4
    )
    1: (
        0: 5
        1: 6
        2: 7
        3: 8
    )
    2: (
        0: 9
        1: 10
        2: 11
        3: 12
    )
)]
cosh$

Read a JSON file into memory:

cosh$ test-data/json2 f<; from-json;
h(
    "asdf": 1
    "qwer": 2
    "tyui": h(
        "asdf": 5
    )
    "zxcv": (
        0: 3
        1: 4
    )
)
cosh$

Get the field names from the JSON file, and print them to standard output:

cosh$ test-data/json2 f<; from-json; keys; println for;
asdf
qwer
tyui
zxcv
cosh$

Find the field names that match a given regex:

cosh$ test-data/json2 f<; from-json; keys; [.{4} m] grep;
v[gen (
    0: asdf
    1: qwer
    2: tyui
    3: zxcv
)]
cosh$

cosh$ test-data/json2 f<; from-json; keys; [a..f m] grep;
v[gen (
    0: asdf
)]
cosh$

Define and use a new function:

cosh$ : add-5 5 +; ,,
cosh$ (1 2 3) add-5 map;
(
    0: 6
    1: 7
    2: 8
)
cosh$

Capture a value using a regex:

cosh$ test-data ls;
v[gen (
    0: test-data/json-bigint
    1: test-data/json2
    2: test-data/json1
    3: test-data/readfile
    4: test-data/csv
    5: test-data/split
)]
cosh$ test-data ls; ["/.*" c; shift] map;
v[gen (
    0: /json-bigint
    1: /json2
    2: /json1
    3: /readfile
    4: /csv
    5: /split
)]
cosh$

Print a path's modification time in a specific format:

cosh$ test-data stat; mtime get; from-epoch; %F strftime;
2023-01-20
cosh$

Documentation

Documentation

Licence

See LICENCE.