for-each

for-each is a small, cross-platform Unix-style utility that executes a command once for each line of input, with positional variable expansion and no shell evaluation.

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Quick examples (TL;DR)

# Do a command for all folders in current directory
ls -d * | for-each echo

# Echo each line
printf "foo\nbar\n" | for-each echo

# Same idea, from a file
cat urls.txt | for-each echo
cat urls.txt | for-each wget

# Show line numbers
cat file.txt | for-each echo '$#'

# Clone many repositories
cat repos.txt | for-each git clone

# Use fields from tab-separated input
printf "apple\tfruit\ncarrot\tvegetable\n" | for-each echo "$1 is a $2"

# Use the full line explicitly
printf "hello world\n" | for-each echo "Input was: $*"

Note: Use single quotes around placeholders (to avoid shell expansion before being passed to for-each): '$1' '$*' '$#'

Example use

# Show help and exit
for-each -h
for-each --help

# Show version number and exit
for-each --version

# Do a command for all folders in current directory
ls -d */ | for-each echo

cat repo_list.txt | for-each echo

# Clone multiple repos
cat repo_list.txt | for-each git clone

s# Run a command with replacement
cat urls.txt | for-each wget

# Line numbers
cat src/main.cpp | for-each echo '$#'

Git & Repository Management

# Clone many repos (one per line)
cat repos.txt | for-each git clone

# Or with submodules
cat repos.txt | for-each git clone --recurse-submodules

File Processing & Renaming

# Convert all markdown to HTML
ls *.md | for-each pandoc '$1' -o '$*.html'

# Compress images
ls *.png | for-each convert '$1' -quality 85 'optimized/$1'

Data Processing Pipelines

# Process TSV/CSV with multi-field access

cat data.tsv | for-each \
    curl -X POST https://api.example.com -d "user=$1&action=$2&value=$3"

# Generate reports per user
cat users.txt | for-each generate-report --user $1 --output reports/$1.pdf

AI / LLM Workflows

ls *.* | for-each runai -t "Say hi" --dummy

# Generate prompts for many countries
cat countries.txt | for-each runai -t '"List top 10 longevity research organizations in $1"'

System Administration

# Restart services across many hosts (from file)
cat hosts.txt | for-each ssh '$1' sudo systemctl restart myapp

# Check disk usage on remote servers
cat servers.txt | for-each ssh '$1' df -h /

# Kill processes by name on multiple machines
cat machines.txt | for-each ssh '$1' pkill -f naughty-process

Media & Bulk Operations

# Download many URLs
cat urls.txt | for-each wget
cat urls.txt | for-each wget -q '$1'

# Resize all videos in a directory
ls *.mp4 | for-each ffmpeg -i '$1' -vf scale=1280:720 r

Features

• Reads lines from stdin
• Executes a command once per line
• Simple variable expansion:
  • $1, $2, … — positional fields
  • $* — entire input line
  • $# — line number (1-based)
• one input line → one argument
• Optional tab-separated fields detected automatically
• Works on Linux, macOS, and Windows
• No runtime dependencies

for-each is intentionally not a CSV (Comma-Separated Values) or text-processing language.

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Installation

Build from source

Build with CMake using the helpers:

./build.sh

On Windows, build with:

./build.bat

To use, install to:

~/.local/bin/for-each

Ensure ~/.local/bin is in your PATH.

License

MIT License

Copyright © 2026 David Joffe

Author

David Joffe https://djoffe.com https://davidjoffe.github.io https://www.tshwanedje.com