System Requirements Document for webserver-shell-bash

1. Introduction

This document specifies webserver-shell-bash, a deliberately simple web server that exposes a bash shell through the browser. The product intent is narrow and explicit: run a web server, and let a person open a page served by it and execute bash commands against that server, reading the returned output in the browser — without needing a local terminal.

The audience is the Web Shell Operator: a technical user who values speed, legibility, and unambiguous state. The product is a control surface, not a marketing site. Success means a visitor can reach the served page, open the shell, submit a bash command, and see its output and exit status returned by the server.

The governing constraint is simplicity. The server stays simple; the shell is the product.

2. System Overview

The system is a single web server process that does two things:

1. Serves a small set of web pages over HTTP.
2. Accepts bash commands submitted from the browser, executes them on the server host, and returns their output to the browser.

Actors

• Web Shell Operator (human, active) — opens the served pages and runs bash commands in the browser.
• Web server process (system) — serves the pages and executes submitted bash commands.
• Bash shell on the server host (system) — the execution environment for submitted commands.

Accepted behavior

• A simple web server is built and run.
• The web server includes a bash shell accessible through it.
• The server is running and reachable before the operator can access the Landing page and the Shell.
• The server executes submitted bash commands and returns their output to the browser.

Ownership

• The Landing page is a first-party, anonymously reachable entry surface that explains the product and directs the visitor to the shell.
• The Shell page is a first-party, anonymously reachable workspace for entering commands, executing them on the server, and viewing returned output.
• Command execution and output capture are owned by the web server process; the browser owns command entry and output display.

Exclusions

• No account, login, or identity system is part of this product.
• No adjacent capabilities (file management UI, multi-user sessions, deployment tooling, dashboards, analytics) are in scope.
• No marketing feature grid or capability claims beyond what the simple server actually does.

2a. Product Interpretation and Delivery Boundary

The product is delivered as a first-party web application served by the web server itself. Both pages are reachable anonymously: there is no identity, session, or permission layer, and none is required, because the accepted journeys involve a single operator interacting with a shell on a server they have reached — no durable actor-specific state, commitment, entitlement, or value transfer must be bound to a particular person.

The delivery boundary is:

• Current: the web server, the Landing page, the Shell page, browser-to-server command submission, server-side bash execution, and returned output.
• Not current: anything beyond a simple server with a browser-accessible bash shell. No future features are specified by the source.

The server must be running and reachable before either page can be used; this is a deployment prerequisite, not a product capability.

2c. Page Content and Component Coverage

Landing

• Information and state: the product identity — a web server with a bash shell — and the fact that the shell is reachable from this page. A live status line reflecting whether the server is reachable.
• Primary action: open the Shell.
• Supporting actions: none beyond navigation to the Shell.
• Domain entities: server host, port, status, uptime (as displayed metadata).
• Component responsibilities:
  • Oversized flush-left headline stating the product in plain terms.
  • A full-width red rule acting as the section divider.
  • A station-board metadata strip (HOST · PORT · STATUS · UPTIME) in uppercase tracked labels with tabular values, separated by hairline dividers.
  • A flat red rectangular call to action, "OPEN SHELL →", cut into the composition at the end of the strip.
  • A colour-coded connection diagram (browser → HTTP → bash → stdout) drawn from flat rectangles, rules, and primary red/yellow.
  • A numbered left rail (01 OVERVIEW / 02 SHELL / 03 PROTOCOL) with the active section marked by a solid red block.
• States:
  • Loading: metadata values render as placeholder rules until the server responds.
  • Empty: not applicable — the page always has content.
  • Success: metadata strip shows live host, port, status, and uptime; the status indicator reads as connected.
  • Error: if the server is unreachable, the status indicator reads as disconnected and the metadata values are shown as unavailable; the Shell link remains visible but the Shell page will report the same failure.
  • Recovery: reloading the page re-attempts the status check.

Shell

• Information and state: the current connection state to the server, the working directory of the shell, and the recent command history. The command/output table is the primary state.
• Primary action: submit a bash command for execution on the server.
• Supporting actions: read returned output, read the exit code of the last command, review recent commands.
• Domain entities: command, output (stdout/stderr), exit code, working directory, connection state, timestamp.
• Component responsibilities:
  • A ruled command/output table: each command row has a red prompt glyph, the command in off-white, and its output in a muted mono block.
  • An exit code shown as a colour-coded tabular cell.
  • A command input control at the active prompt.
  • A right-hand column of state panels: connection, working directory, recent commands.
  • A fixed top bar carrying the live status line.
  • A numbered left rail (01 OVERVIEW / 02 SHELL / 03 PROTOCOL) with the active section marked by a solid red block.
• States:
  • Loading: the workspace renders with an empty command/output table and a status line indicating the connection is being established.
  • Empty: no commands have been run yet; the table shows only the active prompt and a short instruction to enter a command.
  • Success: the submitted command appears as a row with its output and exit code; the prompt returns for the next command.
  • Error: if the command fails, its stderr output and non-zero exit code are shown in the same row, colour-coded as an error; if the server is unreachable, the status line reads as disconnected and the input is disabled with a message stating the server cannot be reached.
  • Recovery: after a failed command, the operator can immediately enter another command; after a connection failure, reloading the page re-attempts the connection.

3. Functional Requirements

FR-1 — Build a simple web server (explicit) As a Web Shell Operator, I should have a simple web server running so that I can reach the product in a browser.

• Trigger: the server process is started.
• Observable result: the server responds to HTTP requests and serves the product's pages.
• Failure/recovery: if the server is not running, no page is reachable; starting the server restores access.
• Continuation: once reachable, the operator can open the Landing page.

FR-2 — Access a bash shell through the web server (explicit) As a Web Shell Operator, I should be able to reach a bash shell through the web server so that I can run commands without a local terminal.

• Trigger: the operator opens the Shell page from the Landing page.
• Observable result: the Shell page presents a command input at an active prompt.
• Access state: the Shell page is anonymously reachable; no identity is required.
• Failure/recovery: if the Shell page cannot be reached, the operator returns to the Landing page and retries.
• Continuation: the operator can enter a command.

FR-3 — Server reachable before page access (required_inference) As a Web Shell Operator, I should only be able to reach the Landing page and the Shell once the web server is running and reachable, so that the pages I see reflect a live server.

• Trigger: the operator requests a page.
• Observable result: pages are served only while the server process is running; the status line reflects reachability.
• Failure/recovery: if the server is down, the request fails and the operator restarts the server.
• Continuation: once reachable, the operator proceeds to the Landing page or the Shell.

FR-4 — Execute submitted bash commands and return output (required_inference) As a Web Shell Operator, I should be able to submit a bash command and see its output returned in the browser, so that I can work in the shell through the web interface.

• Trigger: the operator submits a command at the prompt.
• Observable result: the command is executed on the server host by bash, and its stdout/stderr and exit code are returned and displayed as a row in the command/output table.
• Failure/recovery: a failing command returns its stderr and a non-zero exit code in the same row; the operator can immediately submit another command.
• Continuation: the prompt returns and the operator can run further commands.

FR-5 — View connection, working directory, and recent commands (required_inference) As a Web Shell Operator, I should be able to see the connection state, the shell's working directory, and my recent commands, so that I know the state of the session at a glance.

• Trigger: the Shell page is open and commands are run.
• Observable result: the state panels show the live connection state, the current working directory, and a list of recent commands.
• Failure/recovery: if the connection state cannot be determined, the panel reads as disconnected.
• Continuation: the operator uses this state to decide the next command.

4. User Personas

Web Shell Operator

Product context. The operator is a technical user who needs to run bash commands on a server and does not want to open a local terminal or SSH session to do it. They reach the product by pointing a browser at the running web server.

Primary goal. Execute bash commands through the browser and read their output, quickly and without ambiguity.

Distinct accepted responsibilities.

• Open the Landing page and confirm the server is reachable.
• Open the Shell from the Landing page.
• Enter a bash command at the prompt and submit it.
• Read the returned output and the exit code of the command.
• Read the connection state, working directory, and recent commands to orient the next action.
• Recover from a failed command by entering another command, and from a connection failure by reloading.

Relevant inputs and decisions. The command text to run; whether the returned output and exit code indicate success or failure; whether to continue with another command.

Interactions with other accepted participants. The operator interacts with the web server process (which serves the pages and executes commands) and, indirectly, with the bash shell on the server host (which produces the output). There are no other human participants.

Observable success. A command submitted in the browser appears as a row in the command/output table with its output and exit code, and the prompt returns for the next command.

What makes this role distinct. The operator's work is command-and-response against a live server: the value of the product is the round trip from browser input to bash execution to displayed output. This is not a browsing or content-consumption role, and it is not an administrative role over other users — there are no other users.

5. Core User Flows

Flow 1 — Reach the product and open the shell

1. The Web Shell Operator starts (or is told) that the web server is running, and opens the server's address in a browser.
2. The server serves the Landing page. The operator sees the headline, the red rule, and the metadata strip showing HOST · PORT · STATUS · UPTIME, with the status indicator reading as connected.
3. The operator reads the connection diagram (browser → HTTP → bash → stdout) and understands that the shell runs on the server.
4. The operator selects OPEN SHELL →.
5. The Shell page opens with an empty command/output table, the active prompt, and the state panels showing the connection, working directory, and an empty recent-commands list.
6. Failure/recovery: if the server is unreachable, the Landing page's status indicator reads as disconnected and the metadata values are unavailable; the operator restarts the server and reloads the page.
7. Continuation: the operator proceeds to Flow 2.

Flow 2 — Run a bash command and read its output

1. On the Shell page, the operator types a bash command at the active prompt.
2. The operator submits the command.
3. The web server executes the command with bash on the server host.
4. The command appears as a row in the command/output table: a red prompt glyph, the command in off-white, and its output in a muted mono block, with the exit code shown as a colour-coded tabular cell.
5. The state panels update: the working directory reflects any change the command made, and the command is added to the recent-commands list.
6. The prompt returns for the next command.
7. Failure/recovery: if the command fails, its stderr output and non-zero exit code are shown in the same row, colour-coded as an error; the operator reads the error and immediately enters a corrected command.
8. Continuation: the operator repeats steps 1–6 for further commands.

Flow 3 — Recover from a lost connection

1. While working on the Shell page, the operator submits a command and the server does not respond.
2. The status line reads as disconnected, and the command input is disabled with a message stating the server cannot be reached.
3. The operator restarts the web server.
4. The operator reloads the Shell page.
5. The workspace renders again with the connection state restored, and the operator resumes entering commands.

6. Visuals, Colors, and Theme

The visual system is Massimo Vignelli's information-design language applied to a developer tool: a visible grid, one grotesque used at few sizes, and primary colours as wayfinding. The headline idea is transit-signage rigor for a shell — command, output, and connection state legible at a glance.

Mode: dark.

Colour tokens (exact hex, by role):

No blue anywhere; colour is code, not decoration.

Typography:

• Headings: Archivo — grotesque, flush-left ragged-right, mostly uppercase for labels with 0.08em tracking; headlines set heavy (700–800) and very large with tight leading (0.95); body and UI at 400/500. One family; hierarchy carried by weight, size, and rules — never by a second typeface.
• Body: Archivo.
• Scale: 1.333 modular — display 56px mobile / 88px tablet / 132px desktop; section head 28/36/44; label 12px uppercase tracked; body 16/17; terminal mono 13/14. Line-height 0.95 for display, 1.55 for body.

Shape language: hard edges only — 0px radii, 1px and 3px rules as structure, hairline dividers between every data row, tabular alignment. Panels are rectangles on a visible column grid; no shadows, no glass, no rounded cards. Colour blocks are flat and rectangular, like wayfinding signage.

Layout: a 12-column grid with a permanent left rail (numbered sections: 01 OVERVIEW, 02 SHELL, 03 PROTOCOL) and a fixed top bar carrying the live status line. Landing: asymmetric editorial hero — oversized headline spanning columns 1–9, a red rule under it, and a metadata block (host, port, uptime) in columns 10–12. Shell: full-height workspace split 2:1 — terminal pane on the left with a ruled command/output table, a right column of state panels (connection, working directory, recent commands). Everything aligns to the grid; nothing floats.

Imagery: no photography. Imagery is the interface itself: a ruled command/output table, mono-spaced output blocks, a colour-coded connection diagram (browser → HTTP → bash → stdout), and a small pictogram set for states (running, waiting, error, done). Any decorative graphic is a schematic, drawn with rules and flat colour.

Readable-text rule: headlines, wordmarks, labels, numbers, and controls stay entirely inside the viewport and their container at 375px, 768px, and 1280px, wrapping or scaling (for example font-size: clamp(...) with its mobile size) to fit. Crops and bleeds are for decoration only — shapes, textures, rules, and background art.

7. Signature Design Concept

The Landing first screen is a signage composition, not a SaaS hero.

A 9-column headline in heavy Archivo — "A WEB SERVER WITH A BASH SHELL" — is stacked in three flush-left lines at 132px desktop / 56px mobile, sitting on the near-black ground (#0E0E0E), with a 3px red rule (#E01B24) running the full content width beneath it.

Under the rule, a horizontal metadata strip — HOST · PORT · STATUS · UPTIME — in uppercase 12px tracked labels with tabular values, separated by hairline dividers, like a station board.

The single call to action, "OPEN SHELL →", is a flat red rectangle cut into the composition at the end of the strip, not a centred button.

Below the strip, the colour-coded connection diagram (browser → HTTP → bash → stdout) is drawn only from flat rectangles, rules, and primary red/yellow.

No gradient, no blob, no centred stack. The dominant element is the type and the rule; the palette roles are black ground, off-white type, red as the one wayfinding accent.

8. Interaction Model & Motion Direction

Interaction Model: Static (direction) Motion Tempo: still Hero Dimensionality: flat

Landing Hero Motion Brief

• Focal subject: the oversized flush-left headline and the full-width red rule beneath it, with the station-board metadata strip.
• Input → transformation → outcome thesis: the operator arrives at the server address → the page renders as a signage composition with the live status line and metadata strip → the operator reads the state and selects "OPEN SHELL →" to enter the shell. No motion is required for the thesis; the state is legible in the first frame.
• Motion vocabulary: minimal and instant, like a departure board — output lines appear without fade-in flourish, the status dot switches state in one frame, and the only ambient motion is a 1.2s blinking prompt cursor. Section transitions are hard cuts on scroll; no parallax, no easing theatrics.
• Composed first frame: near-black ground, three flush-left lines of heavy Archivo, a 3px red rule spanning the content width, and the metadata strip with hairline dividers and the flat red "OPEN SHELL →" rectangle at its end.
• Reduced-motion state: the blinking prompt cursor stops and holds a steady visible state; all other elements are already static.

9. Non-Functional Requirements

NFR-1 — Simplicity (explicit) The web server must stay simple. The product consists of the server, the Landing page, and the Shell page; no adjacent capabilities are added.

NFR-2 — Reachability prerequisite (required_inference) The web server must be running and reachable before the Landing page and the Shell can be accessed. This is a deployment prerequisite, not a product feature.

NFR-3 — Legibility (explicit, from creative direction) Command, output, and connection state must be legible at a glance: tabular alignment, hairline dividers between data rows, and colour used as code (red for the active prompt and live state, yellow for warnings and running state, muted for timestamps and exit codes).

NFR-4 — Responsive integrity (explicit, from creative direction) Headlines, labels, numbers, and controls must remain entirely inside the viewport and their container at 375px, 768px, and 1280px, wrapping or scaling to fit. Crops and bleeds are permitted only for decoration.

NFR-5 — No identity layer (required_inference) No account, login, or permission system is required or provided. Both pages are anonymously reachable, because no durable actor-specific state, commitment, entitlement, or value transfer must be bound to a particular person.

10. Tech Stack

• Web server: a simple HTTP server process that serves the pages and executes submitted bash commands. (explicit — the product is a web server with a bash shell)
• Shell execution: bash on the server host. (explicit)
• Frontend: React for the Landing and Shell pages. (default — not specified by user)
• Backend: Python/FastAPI for the server process and the command-execution endpoint. (default — not specified by user)
• Storage: none required; the product holds no durable state beyond the running shell session. (default — not specified by user)
• Containerization: Docker/docker-compose for running the server. (default — not specified by user)

11. Assumptions and Constraints

Assumptions

• The operator has network access to the running web server. (required_inference)
• The server host has bash available. (required_inference)
• The operator is trusted to run commands on the server host; no authorization layer is part of this product. (required_inference)

Constraints

• Keep the web server simple. (explicit)
• The web server must include a bash shell accessible through it. (explicit)
• No account, login, or identity system. (required_inference, consistent with the accepted journeys)
• No adjacent capabilities beyond the simple server and its shell. (explicit)

12. Glossary

• Web Shell Operator — the human user who opens the served pages and runs bash commands in the browser.
• Landing — the anonymously reachable entry page that explains the product and directs the visitor to the shell.
• Shell — the anonymously reachable workspace for entering bash commands, executing them on the server, and viewing returned output.
• Command/output table — the ruled table on the Shell page in which each command row shows a red prompt glyph, the command, its output, and its exit code.
• Exit code — the numeric status returned by a completed bash command, displayed as a colour-coded tabular cell.
• Connection state — whether the browser can currently reach the web server, shown in the status line and the connection panel.
• Working directory — the current directory of the shell session, shown in a state panel on the Shell page.