Ash

Ash is a shell imperative and scripting language first appearing in 1989.

Hello World

#!/usr/bin/env ash

echo "Hello World!"

Coding Guide

Code format

• Fragment. One or more lines of valid ash.

Minimal fragment (copy and adapt)

echo "Hello from fragment!"

Language Version

ash (Almquist Shell) - POSIX-compliant shell

Execution Model

• Interpreted shell script; runs line-by-line. Uses shebang #!/usr/bin/env ash (Alpine/busybox).

Key Characteristics

• POSIX-compliant shell (subset of sh)
• Case-sensitive; variables: VAR=value (no spaces around =)
• Command substitution: `command` or $(command); interpolation: "$VAR"
• No arrays (unlike bash); limited built-ins

Fragment Authoring

Write valid ash commands.

Available Commands

Standard POSIX utilities are available:

• echo - Print text
• printf - Formatted output
• test / [ - Conditional tests
• if, while, for - Control structures
• grep, sed, awk - Text processing (if installed)
• Standard Unix utilities

Common Patterns

• Output: echo "message" or printf "%s\n" "message"
• Variables: NAME="value" and echo "$NAME"
• Conditionals: if [ condition ]; then ... fi
• Loops: for i in 1 2 3; do echo "$i"; done
• Command substitution: RESULT=$(command)
• Arithmetic: expr 1 + 2 or $((1 + 2)) (if supported)

Examples

# Simple output
echo "Hello from fragment!"

# Variables
NAME="Alice"
echo "Hello, $NAME!"

# Arithmetic
A=5
B=10
SUM=$((A + B))
echo "Sum: $SUM"

# Loops
for i in 1 2 3 4 5; do
    echo "Count: $i"
done

# Conditionals
if [ "$1" = "test" ]; then
    echo "Testing mode"
else
    echo "Normal mode"
fi

# Command substitution
DATE=$(date)
echo "Current date: $DATE"

Caveats

• Stdin and $* work when the script is run with a pipe or arguments.
• ash is a minimal shell - fewer features than bash
• No arrays (use space-separated strings instead)
• Limited arithmetic expansion (may need expr)
• Variable assignment: no spaces around =
• Use [ for tests, not [[ (bashism)
• Quote variables to prevent word splitting: "$VAR"
• Case-sensitive variable names
• Limited built-in string manipulation (may need external tools)

Fraglet Scripts

Echo Args

#!/usr/bin/env -S fragletc --vein=ash
echo "Args: $*"

Stdin Upper

#!/usr/bin/env -S fragletc --vein=ash
while read -r line; do echo "$line" | tr "a-z" "A-Z"; done

Test

#!/usr/bin/env -S fragletc --vein=ash

echo "Hello World!"

Connections

Container Info