Bash

Overview

Bash is ideal for system operations, file manipulation, and quick shell scripting. Runner Codes provides Bash 5.2 on Alpine Linux with BusyBox utilities.

Specifications

Property	Value
Docker Image	alpine:3.20 + bash
Version	Bash 5.2.26
Rootfs Size	100 MB
Execution	Interpreted
File Extension	.sh
Run Command	bash {file}
Execution Time	~5ms

1. Create Rootfs from Docker

sudo infra.operator rootfs from-docker --name bash --image alpine:3.20 --size 100

2. Create Snapshot

sudo infra.operator snapshot create --lang bash --mem 256 --vcpus 1

3. Upload rootfs to S3

sudo infra.operator rootfs upload --lang bash --bucket runner-codes

3. Upload snapshot to S3

sudo infra.operator snapshot upload --lang bash --bucket runner-codes

4. Test Execution

sudo infra.operator host --lang bash --code "bash --version | head -1" --mem 256 --vcpus 1 --snapshot

Execution Flow

Examples

Hello World

Request

{
  "trace_id": "bash-hello-001",
  "lang": "bash",
  "code": "echo 'Hello from Bash!'",
  "timeout": 10
}

Response

{
  "trace_id": "bash-hello-001",
  "stdout": "Hello from Bash!\n",
  "stderr": "",
  "exit_code": 0
}

Variables

Request

{
  "trace_id": "bash-vars-001",
  "lang": "bash",
  "code": "name=\"Alice\"\nage=30\necho \"Name: $name\"\necho \"Age: $age\"\necho \"Combined: ${name} is ${age} years old\"",
  "timeout": 10
}

Response

{
  "trace_id": "bash-vars-001",
  "stdout": "Name: Alice\nAge: 30\nCombined: Alice is 30 years old\n",
  "stderr": "",
  "exit_code": 0
}

Arithmetic

Request

{
  "trace_id": "bash-math-001",
  "lang": "bash",
  "code": "a=10\nb=20\nsum=$((a + b))\nproduct=$((a * b))\necho \"Sum: $sum\"\necho \"Product: $product\"\necho \"Division: $((a / 2))\"\necho \"Modulo: $((b % 3))\"",
  "timeout": 10
}

Response

{
  "trace_id": "bash-math-001",
  "stdout": "Sum: 30\nProduct: 200\nDivision: 5\nModulo: 2\n",
  "stderr": "",
  "exit_code": 0
}

Arrays

Request

{
  "trace_id": "bash-array-001",
  "lang": "bash",
  "code": "fruits=(apple banana cherry)\necho \"First: ${fruits[0]}\"\necho \"All: ${fruits[@]}\"\necho \"Count: ${#fruits[@]}\"\n\n# Add element\nfruits+=(date)\necho \"After adding: ${fruits[@]}\"\n\n# Loop\nfor fruit in \"${fruits[@]}\"; do\n    echo \"- $fruit\"\ndone",
  "timeout": 10
}

Response

{
  "trace_id": "bash-array-001",
  "stdout": "First: apple\nAll: apple banana cherry\nCount: 3\nAfter adding: apple banana cherry date\n- apple\n- banana\n- cherry\n- date\n",
  "stderr": "",
  "exit_code": 0
}

Conditionals

Request

{
  "trace_id": "bash-cond-001",
  "lang": "bash",
  "code": "x=10\n\nif [ $x -gt 5 ]; then\n    echo \"x is greater than 5\"\nfi\n\nif [ $x -eq 10 ]; then\n    echo \"x equals 10\"\nelse\n    echo \"x is not 10\"\nfi\n\n# String comparison\nname=\"Alice\"\nif [[ \"$name\" == \"Alice\" ]]; then\n    echo \"Hello, Alice!\"\nfi",
  "timeout": 10
}

Response

{
  "trace_id": "bash-cond-001",
  "stdout": "x is greater than 5\nx equals 10\nHello, Alice!\n",
  "stderr": "",
  "exit_code": 0
}

Loops

Request

{
  "trace_id": "bash-loop-001",
  "lang": "bash",
  "code": "# For loop with range\necho \"For loop:\"\nfor i in {1..5}; do\n    echo \"  Iteration: $i\"\ndone\n\n# While loop\necho \"While loop:\"\ncount=0\nwhile [ $count -lt 3 ]; do\n    echo \"  Count: $count\"\n    ((count++))\ndone",
  "timeout": 10
}

Response

{
  "trace_id": "bash-loop-001",
  "stdout": "For loop:\n  Iteration: 1\n  Iteration: 2\n  Iteration: 3\n  Iteration: 4\n  Iteration: 5\nWhile loop:\n  Count: 0\n  Count: 1\n  Count: 2\n",
  "stderr": "",
  "exit_code": 0
}

Functions

Request

{
  "trace_id": "bash-func-001",
  "lang": "bash",
  "code": "greet() {\n    local name=$1\n    echo \"Hello, $name!\"\n}\n\nadd() {\n    local a=$1\n    local b=$2\n    echo $((a + b))\n}\n\ngreet \"World\"\nresult=$(add 5 3)\necho \"5 + 3 = $result\"",
  "timeout": 10
}

Response

{
  "trace_id": "bash-func-001",
  "stdout": "Hello, World!\n5 + 3 = 8\n",
  "stderr": "",
  "exit_code": 0
}

String Operations

Request

{
  "trace_id": "bash-string-001",
  "lang": "bash",
  "code": "str=\"Hello, World!\"\n\necho \"Original: $str\"\necho \"Length: ${#str}\"\necho \"Uppercase: ${str^^}\"\necho \"Lowercase: ${str,,}\"\necho \"Substring (0-5): ${str:0:5}\"\necho \"Replace: ${str/World/Bash}\"",
  "timeout": 10
}

Response

{
  "trace_id": "bash-string-001",
  "stdout": "Original: Hello, World!\nLength: 13\nUppercase: HELLO, WORLD!\nLowercase: hello, world!\nSubstring (0-5): Hello\nReplace: Hello, Bash!\n",
  "stderr": "",
  "exit_code": 0
}

File Operations

Request

{
  "trace_id": "bash-file-001",
  "lang": "bash",
  "code": "# Write file\necho -e \"Line 1\\nLine 2\\nLine 3\" > /tmp/test.txt\n\n# Read file\necho \"File contents:\"\ncat /tmp/test.txt\n\n# Line count\necho \"Line count: $(wc -l < /tmp/test.txt)\"\n\n# Check if file exists\nif [ -f /tmp/test.txt ]; then\n    echo \"File exists\"\nfi",
  "timeout": 10
}

Response

{
  "trace_id": "bash-file-001",
  "stdout": "File contents:\nLine 1\nLine 2\nLine 3\nLine count: 3\nFile exists\n",
  "stderr": "",
  "exit_code": 0
}

Pipes and Redirection

Request

{
  "trace_id": "bash-pipe-001",
  "lang": "bash",
  "code": "# Create sample data\necho -e \"apple\\nbanana\\napricot\\nblueberry\\ncherry\" > /tmp/fruits.txt\n\n# Filter with grep\necho \"Fruits starting with 'a':\"\ngrep '^a' /tmp/fruits.txt\n\n# Count\necho \"Count: $(grep -c '^a' /tmp/fruits.txt)\"\n\n# Sort\necho \"Sorted:\"\nsort /tmp/fruits.txt\n\n# Pipeline\necho \"Pipeline (sort | head -3):\"\nsort /tmp/fruits.txt | head -3",
  "timeout": 10
}

Response

{
  "trace_id": "bash-pipe-001",
  "stdout": "Fruits starting with 'a':\napple\napricot\nCount: 2\nSorted:\napple\napricot\nbanana\nblueberry\ncherry\nPipeline (sort | head -3):\napple\napricot\nbanana\n",
  "stderr": "",
  "exit_code": 0
}

System Information

Request

{
  "trace_id": "bash-sysinfo-001",
  "lang": "bash",
  "code": "echo \"Hostname: $(hostname)\"\necho \"User: $(whoami)\"\necho \"PWD: $(pwd)\"\necho \"Date: $(date)\"\necho \"Uptime: $(uptime)\"\necho \"Kernel: $(uname -r)\"",
  "timeout": 10
}

Response

{
  "trace_id": "bash-sysinfo-001",
  "stdout": "Hostname: localhost\nUser: root\nPWD: /tmp/job-bash-sysinfo-001\nDate: Fri Nov 29 10:30:45 UTC 2024\nUptime: 10:30:45 up 0 min, 0 users, load average: 0.00, 0.00, 0.00\nKernel: 5.10.0\n",
  "stderr": "",
  "exit_code": 0
}

AWK Processing

Request

{
  "trace_id": "bash-awk-001",
  "lang": "bash",
  "code": "# Create CSV data\ncat << 'EOF' > /tmp/data.csv\nname,age,city\nAlice,30,NYC\nBob,25,LA\nCharlie,35,Chicago\nEOF\n\necho \"Original:\"\ncat /tmp/data.csv\n\necho \"\\nNames only:\"\nawk -F',' 'NR>1 {print $1}' /tmp/data.csv\n\necho \"\\nSum of ages:\"\nawk -F',' 'NR>1 {sum+=$2} END {print sum}' /tmp/data.csv",
  "timeout": 10
}

Response

{
  "trace_id": "bash-awk-001",
  "stdout": "Original:\nname,age,city\nAlice,30,NYC\nBob,25,LA\nCharlie,35,Chicago\n\nNames only:\nAlice\nBob\nCharlie\n\nSum of ages:\n90\n",
  "stderr": "",
  "exit_code": 0
}

Sed Processing

Request

{
  "trace_id": "bash-sed-001",
  "lang": "bash",
  "code": "# Create sample text\necho -e \"Hello World\\nHello Universe\\nGoodbye World\" > /tmp/text.txt\n\necho \"Original:\"\ncat /tmp/text.txt\n\necho \"\\nReplace 'World' with 'Earth':\"\nsed 's/World/Earth/g' /tmp/text.txt\n\necho \"\\nDelete lines with 'Goodbye':\"\nsed '/Goodbye/d' /tmp/text.txt\n\necho \"\\nAdd prefix to each line:\"\nsed 's/^/>> /' /tmp/text.txt",
  "timeout": 10
}

Response

{
  "trace_id": "bash-sed-001",
  "stdout": "Original:\nHello World\nHello Universe\nGoodbye World\n\nReplace 'World' with 'Earth':\nHello Earth\nHello Universe\nGoodbye Earth\n\nDelete lines with 'Goodbye':\nHello World\nHello Universe\n\nAdd prefix to each line:\n>> Hello World\n>> Hello Universe\n>> Goodbye World\n",
  "stderr": "",
  "exit_code": 0
}

JSON with jq

Request

{
  "trace_id": "bash-jq-001",
  "lang": "bash",
  "code": "# Create JSON data\ncat << 'EOF' > /tmp/data.json\n{\n  \"users\": [\n    {\"name\": \"Alice\", \"age\": 30},\n    {\"name\": \"Bob\", \"age\": 25}\n  ]\n}\nEOF\n\n# Note: jq might not be available in minimal rootfs\n# This example shows the intent\necho \"JSON content:\"\ncat /tmp/data.json",
  "timeout": 10
}

Response

{
  "trace_id": "bash-jq-001",
  "stdout": "JSON content:\n{\n  \"users\": [\n    {\"name\": \"Alice\", \"age\": 30},\n    {\"name\": \"Bob\", \"age\": 25}\n  ]\n}\n",
  "stderr": "",
  "exit_code": 0
}

Complex Test: Comprehensive Bash

Request

{
  "trace_id": "bash-complex-001",
  "lang": "bash",
  "code": "#!/bin/bash\necho '=== Bash Complex Test ==='\necho\n\n# Test 1: Fibonacci\necho '1. Fibonacci sequence:'\nfib() {\n    local n=$1\n    if [ $n -le 1 ]; then\n        echo $n\n    else\n        local a=$(fib $((n-1)))\n        local b=$(fib $((n-2)))\n        echo $((a + b))\n    fi\n}\necho -n '   First 10: '\nfor i in {0..9}; do\n    echo -n \"$(fib $i) \"\ndone\necho\n\n# Test 2: Array operations and sorting\necho\necho '2. Array sorting (bubble sort):'\narr=(64 34 25 12 22 11 90)\necho \"   Input:  ${arr[*]}\"\nn=${#arr[@]}\nfor ((i=0; i<n-1; i++)); do\n    for ((j=0; j<n-i-1; j++)); do\n        if [ ${arr[j]} -gt ${arr[$((j+1))]} ]; then\n            temp=${arr[j]}\n            arr[j]=${arr[$((j+1))]}\n            arr[$((j+1))]=$temp\n        fi\n    done\ndone\necho \"   Output: ${arr[*]}\"\n\n# Test 3: Associative arrays\necho\necho '3. Associative arrays:'\ndeclare -A user\nuser[name]='Alice'\nuser[age]=30\nuser[city]='NYC'\nfor key in \"${!user[@]}\"; do\n    echo \"   $key: ${user[$key]}\"\ndone\n\n# Test 4: Text processing\necho\necho '4. Text processing:'\ntext='Hello World from Bash Script'\necho \"   Original: $text\"\necho \"   Uppercase: ${text^^}\"\necho \"   Lowercase: ${text,,}\"\necho \"   Word count: $(echo $text | wc -w)\"\necho \"   Char count: ${#text}\"\n\n# Test 5: Arithmetic and math\necho\necho '5. Arithmetic operations:'\nnumbers=(1 2 3 4 5 6 7 8 9 10)\nsum=0\nfor n in \"${numbers[@]}\"; do\n    sum=$((sum + n))\ndone\necho \"   Numbers: ${numbers[*]}\"\necho \"   Sum: $sum\"\necho \"   Average: $((sum / ${#numbers[@]}))\"\necho \"   Max: $(printf '%s\\n' \"${numbers[@]}\" | sort -rn | head -1)\"\n\n# Test 6: Functions with return values\necho\necho '6. Functions:'\nfactorial() {\n    local n=$1\n    if [ $n -le 1 ]; then\n        echo 1\n    else\n        local prev=$(factorial $((n-1)))\n        echo $((n * prev))\n    fi\n}\necho \"   5! = $(factorial 5)\"\necho \"   7! = $(factorial 7)\"\n\n# Test 7: Pattern matching and regex\necho\necho '7. Pattern matching:'\nfiles=('script.sh' 'main.py' 'app.js' 'test.sh' 'data.json')\necho \"   All files: ${files[*]}\"\necho -n '   Shell scripts: '\nfor f in \"${files[@]}\"; do\n    [[ $f == *.sh ]] && echo -n \"$f \"\ndone\necho\n\n# Test 8: Here documents and data\necho\necho '8. Data processing:'\ncat << 'DATA' > /tmp/data.txt\nAlice,30,NYC\nBob,25,LA\nCharlie,35,Chicago\nDATA\necho '   CSV data:'\nwhile IFS=',' read -r name age city; do\n    echo \"   - $name ($age) from $city\"\ndone < /tmp/data.txt\n\necho\necho '=== All tests passed ==='",
  "timeout": 30
}

Response

{
  "trace_id": "bash-complex-001",
  "stdout": "=== Bash Complex Test ===\n\n1. Fibonacci sequence:\n   First 10: 0 1 1 2 3 5 8 13 21 34 \n\n2. Array sorting (bubble sort):\n   Input:  64 34 25 12 22 11 90\n   Output: 11 12 22 25 34 64 90\n\n3. Associative arrays:\n   name: Alice\n   age: 30\n   city: NYC\n\n4. Text processing:\n   Original: Hello World from Bash Script\n   Uppercase: HELLO WORLD FROM BASH SCRIPT\n   Lowercase: hello world from bash script\n   Word count: 5\n   Char count: 28\n\n5. Arithmetic operations:\n   Numbers: 1 2 3 4 5 6 7 8 9 10\n   Sum: 55\n   Average: 5\n   Max: 10\n\n6. Functions:\n   5! = 120\n   7! = 5040\n\n7. Pattern matching:\n   All files: script.sh main.py app.js test.sh data.json\n   Shell scripts: script.sh test.sh \n\n8. Data processing:\n   CSV data:\n   - Alice (30) from NYC\n   - Bob (25) from LA\n   - Charlie (35) from Chicago\n\n=== All tests passed ===\n",
  "stderr": "",
  "exit_code": 0
}

Available Commands

Category	Commands
File	ls, cat, cp, mv, rm, mkdir, touch, chmod
Text	echo, printf, grep, sed, awk, cut, sort, uniq
Archive	tar, gzip, gunzip
Process	ps, kill
System	date, hostname, whoami, uname, uptime
Math	expr, bc (if installed)
Utilities	head, tail, wc, tr, tee, xargs

note

Network utilities (curl, wget, ping, etc.) are not available as there's no network access.

Error Examples

Syntax Error

Request

{
  "trace_id": "bash-err-syntax",
  "lang": "bash",
  "code": "if [ $x -gt 5 ]\nthen\necho \"test\"",
  "timeout": 10
}

Response

{
  "trace_id": "bash-err-syntax",
  "stdout": "",
  "stderr": "/tmp/job-bash-err-syntax/script.sh: line 4: syntax error: unexpected end of file\n",
  "exit_code": 2
}

Command Not Found

Request

{
  "trace_id": "bash-err-cmd",
  "lang": "bash",
  "code": "curl https://example.com",
  "timeout": 10
}

Response

{
  "trace_id": "bash-err-cmd",
  "stdout": "",
  "stderr": "/tmp/job-bash-err-cmd/script.sh: line 1: curl: command not found\n",
  "exit_code": 127
}

File Not Found

Request

{
  "trace_id": "bash-err-file",
  "lang": "bash",
  "code": "cat /nonexistent/file.txt",
  "timeout": 10
}

Response

{
  "trace_id": "bash-err-file",
  "stdout": "",
  "stderr": "cat: /nonexistent/file.txt: No such file or directory\n",
  "exit_code": 1
}

Performance

Operation	Time
Echo	~10ms
File operations	~20ms
Grep (100 lines)	~30ms
Awk processing	~50ms
Loop (1000 iterations)	~500ms

tip

Bash is the fastest to start since there's no compilation, but computationally intensive operations are slower than compiled languages.

Limitations

warning

The Bash environment has the following limitations:

1. No network: curl, wget, ping not available
2. Limited utilities: Only basic GNU coreutils
3. No package manager: apt-get not functional without network
4. Memory limit: 512 MiB default
5. Timeout: Configurable, default 10 seconds

Exit Codes

Code	Meaning
0	Success
1	General error
2	Syntax error
126	Permission denied
127	Command not found
128+N	Fatal error signal N

Best Practices

Best Practices

• Always quote variables — Use "$var" instead of $var to prevent word splitting.
• Use modern conditionals — Prefer [[ ]] over [ ] for safer string comparisons and regex support.
• Check command existence — Use command -v cmd to check if a command exists before using it.
• Exit on errors — Add set -e at the start to exit on first error.