context-aware-ops

Context-Aware Operations Skill

This skill provides patterns and techniques for managing large files and command outputs efficiently, preventing context window exhaustion while maintaining effective problem-solving capabilities.

When to Use This Skill

• Before reading any file in the codebase
• Before executing commands that might produce large output
• When working with logs, build outputs, or data files
• When searching through codebases
• When debugging issues that might involve large resources

Core Principle

Always check before you dump!

Never blindly dump large resources into your context. Always:

1. Check the size first
2. Use filtering if needed
3. Focus on relevant portions only

File Size Checking

Check Line Count

# Fast line count
wc -l filename.txt

# Line count without filename
wc -l < filename.txt

# Line count with human-readable file size
wc -l filename.txt && ls -lh filename.txt

Check File Size

# Human-readable size
ls -lh filename.txt

# Size in bytes (Linux)
stat -c%s filename.txt

# Size in bytes (macOS)
stat -f%z filename.txt

# Quick check if file is large
[ $(wc -l < filename.txt) -gt 500 ] && echo "Large file" || echo "Small file"

Filtered File Reading

Read Beginning and End

# First 50 lines
head -n 50 filename.txt

# Last 50 lines
tail -n 50 filename.txt

# Both ends with separator
head -n 30 filename.txt && echo "..." && tail -n 30 filename.txt

Read Specific Ranges

# Lines 100-200
sed -n '100,200p' filename.txt

# Around a specific line (line 150 ± 25 lines)
sed -n '125,175p' filename.txt

# Skip first N lines, show next M
tail -n +100 filename.txt | head -n 50

Search-Based Reading

# Find and show context
grep -n "pattern" filename.txt

# Show matching lines with 5 lines of context
grep -C 5 "pattern" filename.txt

# Show matching lines with line numbers
grep -n "pattern" filename.txt | head -20

# Count matches without showing content
grep -c "pattern" filename.txt

Command Output Filtering

Check Output Size First

# Count lines before showing
command | tee >(wc -l >&2) | head -20

# Or separately
output_lines=$(command | wc -l)
echo "Command produced $output_lines lines"
if [ $output_lines -gt 100 ]; then
  command | head -50
else
  command
fi

Filter Common Patterns

# Show only errors and warnings
command 2>&1 | grep -E "error|warn|fail" -i

# Show only specific log levels
command | grep -E "ERROR|WARN|FATAL"

# Exclude verbose/debug lines
command | grep -v -E "DEBUG|TRACE|INFO"

# Show unique errors only
command 2>&1 | grep -i error | sort -u

Paginate Large Output

# First page
command | head -n 50

# Show summary instead of full output
command | wc -l
command | head -20 && echo "... (showing first 20 lines)"
command | tail -20 && echo "... (showing last 20 lines)"

Smart File Viewing Strategy

Decision Tree

#!/bin/bash
FILE=$1

# Check if file exists
if [ ! -f "$FILE" ]; then
  echo "File not found: $FILE"
  exit 1
fi

# Get line count
LINES=$(wc -l < "$FILE")

# Decide how to show the file
if [ $LINES -le 100 ]; then
  # Small file - show all
  cat "$FILE"
elif [ $LINES -le 500 ]; then
  # Medium file - show with indicator
  cat "$FILE"
  echo "--- End of file ($LINES lines) ---"
elif [ $LINES -le 2000 ]; then
  # Large file - show beginning and end
  echo "--- First 50 lines of $LINES ---"
  head -n 50 "$FILE"
  echo "--- ... ---"
  echo "--- Last 50 lines ---"
  tail -n 50 "$FILE"
else
  # Very large file - show summary only
  echo "File has $LINES lines (too large to show)"
  echo "First 30 lines:"
  head -n 30 "$FILE"
  echo "---"
  echo "Last 30 lines:"
  tail -n 30 "$FILE"
  echo "---"
  echo "Use 'grep' to search for specific content"
fi

Working with Logs

Efficient Log Analysis

# Find errors in log
grep -i error logfile.log | head -20

# Show recent errors
tail -1000 logfile.log | grep -i error

# Count error types
grep -i error logfile.log | awk '{print $NF}' | sort | uniq -c | sort -rn

# Show errors with timestamps
grep -i error logfile.log | awk '{print $1, $2, $NF}' | head -20

# Find exceptions with context
grep -B 3 -A 10 "Exception" logfile.log | head -50

Log Sampling

# Show every Nth line (sample large log)
awk 'NR % 10 == 0' large.log | head -100

# Show random sample
shuf -n 50 large.log

# Show first occurrence of each unique error
grep -i error large.log | awk '!seen[$0]++' | head -20

Working with Code

Search Code Efficiently

# Find function definitions (Python example)
grep -n "^def " *.py

# Find class definitions with context
grep -A 5 "^class " *.py | head -50

# Find TODO/FIXME comments
grep -rn "TODO\|FIXME" --include="*.py" | head -20

# Count occurrences per file
grep -rc "pattern" . | grep -v ":0$" | sort -t: -k2 -rn

Browse Large Codebases

# List all Python files with line counts
find . -name "*.py" -exec wc -l {} + | sort -rn | head -20

# Find files containing pattern with size check
for f in $(grep -l "pattern" *.py); do
  lines=$(wc -l < "$f")
  echo "$f: $lines lines"
done

# Show structure without dumping content
find . -type f -name "*.py" | head -30
tree -L 3 --filesfirst 2>/dev/null || find . -type d | head -20

Context Window Budget Management

Track Usage Mentally

• Small files (<100 lines): ~100 tokens per file
• Medium files (100-500 lines): ~500 tokens per file
• Large files (500-2000 lines): Consider partial reading
• Very large files (>2000 lines): Never dump completely

Prioritization Strategy

1. Critical: Files directly related to the bug/feature
2. Important: Dependencies and related modules
3. Nice-to-have: Context and documentation
4. Skip: Tangentially related or very large files

When Context is Running Low

# Instead of full file, show:
# 1. File summary
wc -l filename && head -20 filename

# 2. Function/class list
grep -E "^(def|class|function|export)" filename

# 3. Specific section only
sed -n '/start_marker/,/end_marker/p' filename

# 4. Just the relevant function
awk '/^def target_function/,/^def [^t]/' filename.py

Advanced Techniques

Pipe Chains for Efficiency

# Find, filter, and limit in one go
find . -name "*.log" -exec grep -l "ERROR" {} \; | head -10

# Search multiple files, show unique results
grep -rh "pattern" . | sort -u | head -20

# Complex filtering in stages
cat large.txt | \
  grep -i "keyword" | \
  grep -v "noise" | \
  sort -u | \
  head -30

Binary Search for Large Files

# Find approximate location of pattern
total_lines=$(wc -l < large.txt)
middle=$((total_lines / 2))

# Check first half
head -n $middle large.txt | grep -q "pattern" && echo "In first half" || echo "In second half"

# Then narrow down further

Incremental Reading

# Read file in chunks
chunk_size=100
current=0
total=$(wc -l < file.txt)

# Read first chunk
sed -n "1,${chunk_size}p" file.txt

# If needed, read next chunk
current=$((current + chunk_size))
sed -n "${current},$((current + chunk_size))p" file.txt

Common Pitfalls to Avoid

1. Don't: cat huge_file.log Do: head -100 huge_file.log && echo "... (showing first 100 of $(wc -l < huge_file.log) lines)"

2. Don't: npm install --verbose Do: npm install 2>&1 | grep -E "error|warn" -i || echo "Install successful"

3. Don't: git log Do: git log --oneline -20 or git log --oneline | head -20

4. Don't: docker logs container Do: docker logs --tail 100 container or docker logs container 2>&1 | grep -i error

5. Don't: ./run_tests.sh Do: ./run_tests.sh 2>&1 | tee >(wc -l >&2) | grep -E "fail|error|pass" -i | head -50

Remember

• Size matters: Always check before you dump
• Filter first: Use grep, head, tail, sed, awk
• Focus: Only show what's relevant to the current task
• Summarize: When in doubt, show a summary rather than everything
• Iterate: You can always come back for more details if needed

Your context window is precious - use it wisely!