A reference for using the Bash command shell on Linux and macOS. It explains command chaining, pipes, file searches, processes, ports, logs, and error handling.

Use it to write shell commands and scripts, combine command output, inspect files and logs, manage processes, and find programs using a network port.

It reduces mistakes when running commands, finding files, diagnosing running programs, or handling command failures in a terminal.

bash-linux — Skill by diillson

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods

npx agentmods add skills/diillson/chatcli/bash-linux

Any agent

npx skills add diillson/chatcli --skill bash-linux

Clone the repo

git clone --depth 1 https://github.com/diillson/chatcli

Made for: Claude Code, Codex.

Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,296 The whole file, excluding the scripts and references it only reads on demand.

Security scan B 2 findings. Scan, not verified.

Origin 92% copy Near-identical to another mod in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5	$0.00029	$0.01296
Opus 5	$0.00015	$0.00648
Sonnet 5	$0.00006	$0.00259
Haiku 4.5	$0.00003	$0.00130

Measured 2d ago against content hash 17c0a0d75bf2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

bash-linux scanned grade B with 2 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Sends data to an external URLmediumData exfiltration

A POST to an outside endpoint may be telemetry or may be exfiltration; either way the mod talks to somewhere, and you should know where.

| POST JSON | `curl -X POST -H "Content-Type: application/json" -d '{"key":"value"}' URL` |

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

| Download | `curl -O https://example.com/file` |

Origin

This is a copy

92% identical to bash-linux — 2 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agent/skills/bash-linux/SKILL.md · 200 lines

How it starts

The opening of the file, as written. The whole thing — 200 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Bash Linux Patterns

Essential patterns for Bash on Linux/macOS.

1. Operator Syntax

Chaining Commands

Operator	Meaning	Example
`;`	Run sequentially	`cmd1; cmd2`
`&&`	Run if previous succeeded	`npm install && npm run dev`
`\|\|`	Run if previous failed	`npm test \|\| echo "Tests failed"`
`\|`	Pipe output	`ls \| grep ".js"`

2. File Operations

Essential Commands

Task	Command
List all	`ls -la`
Find files	`find . -name "*.js" -type f`
File content	`cat file.txt`
First N lines	`head -n 20 file.txt`
Last N lines	`tail -n 20 file.txt`
Follow log	`tail -f log.txt`
Search in files	`grep -r "pattern" --include="*.js"`
File size	`du -sh *`
Disk usage	`df -h`

3. Process Management

Task	Command
List processes	`ps aux`
Find by name	`ps aux \| grep node`
Kill by PID	`kill -9 <PID>`
Find port user	`lsof -i :3000`
Kill port	`kill -9 $(lsof -t -i :3000)`
Background	`npm run dev &`
Jobs	`jobs -l`
Bring to front	`fg %1`

4. Text Processing

Core Tools

Tool	Purpose	Example
`grep`	Search	`grep -rn "TODO" src/`
`sed`	Replace	`sed -i 's/old/new/g' file.txt`
`awk`	Extract columns	`awk '{print $1}' file.txt`
`cut`	Cut fields	`cut -d',' -f1 data.csv`
`sort`	Sort lines	`sort -u file.txt`
`uniq`	Unique lines	`sort file.txt \| uniq -c`
`wc`	Count	`wc -l file.txt`

5. Environment Variables

Task	Command
View all	`env` or `printenv`
View one	`echo $PATH`
Set temporary	`export VAR="value"`
Set in script	`VAR="value" command`
Add to PATH	`export PATH="$PATH:/new/path"`

6. Network

Task	Command
Download	`curl -O https://example.com/file`
API request	`curl -X GET https://api.example.com`
POST JSON	`curl -X POST -H "Content-Type: application/json" -d '{"key":"value"}' URL`
Check port	`nc -zv localhost 3000`
Network info	`ifconfig` or `ip addr`

Read the full file on GitHub · 200 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2d ago First seen · 200 lines · 29 tokens per session scan B 17c0a0d75bf2

Subscribe to this mod's changes

bash-linux is a skill published in the GitHub repository diillson/chatcli (89 stars, last pushed 2d ago), licensed Apache-2.0. It adds 29 tokens to every session and 1,296 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it B with 2 findings (sends data to an external url, makes network calls). It is 92% identical to bash-linux, differing in 2 lines, and is treated as a copy.

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bash-linux