Verifying File Changes with Terminal Inspection

The Schrödinger's Cat Problem

When working with files in Obsidian (or any application that watches the filesystem), you might wonder: "Did this file exist before I opened the app, or did opening the app create it?"

This is similar to Schrödinger's cat - the act of observation (opening Obsidian) might affect the state you're trying to verify.

Solution: Use terminal commands to inspect files BEFORE opening the application.

Essential Verification Commands

Check If File Exists

bash
ls -la "path/to/file.md"

Output shows:

• File permissions
• Owner
• Size in bytes
• Modification timestamp (critical!)
• Filename

Example:

bash
ls -la "_Nakul/TEST Obsidian Closed Test.md"
# Output: -rw-r--r--@ 1 user staff 720 Nov 8 14:45 TEST...

Read File Contents

bash
cat "path/to/file.md"

Use when: You want to see exact contents including frontmatter

Pro tip: Use head for just the first lines:

bash
head -15 "path/to/file.md"  # First 15 lines (covers frontmatter)

Detailed File Metadata

macOS:

bash
stat -f "%Sm - %N" "path/to/file.md"

Linux:

bash
stat --format="%y - %n" "path/to/file.md"

Output shows:

• Full modification timestamp with seconds
• Filename

Example output:

Nov  8 14:45:32 2025 - /path/to/file.md

Check Multiple Files at Once

bash
ls -ltr _Nakul/TEST*.md

Flags explained:

• -l = long format (detailed)
• -t = sort by time
• -r = reverse order (newest last)

Use when: Checking creation order of multiple test files

Verification Workflow

Scenario: AI Agent Created a File

Step 1: AI creates file via terminal/API

Step 2: Verify BEFORE opening Obsidian:

bash
# Navigate to vault
cd "/path/to/vault"

# Check file exists and timestamp
ls -la "path/to/new-file.md"

# Read contents to verify frontmatter
head -15 "path/to/new-file.md"

# Get detailed timestamp
stat -f "%Sm" "path/to/new-file.md"

Step 3: Note the timestamp (e.g., "14:45:32")

Step 4: Open Obsidian

Step 5: Verify file appears with same content

Result: You've proven the file existed before Obsidian opened it.

Common Use Cases

1. Verifying Template Processing

Question: Did AI replace Templater syntax or leave it literal?

Command:

bash
grep "<%" "path/to/file.md"

Output:

• If empty: Templates were processed ✅
• If matches found: Literal syntax remains ❌

2. Comparing File Versions

Before editing:

bash
cat "file.md" > /tmp/before.txt

After editing:

bash
cat "file.md" > /tmp/after.txt
diff /tmp/before.txt /tmp/after.txt

Shows exact changes made.

3. Watching File Changes in Real-Time

macOS:

bash
fswatch -o "path/to/file.md" | xargs -n1 -I{} date

Linux:

bash
inotifywait -m "path/to/file.md"

Prints timestamp every time file is modified.

4. Finding Recently Modified Files

bash
find . -name "*.md" -mtime -1

Lists all .md files modified in last 24 hours.

More specific:

bash
find . -name "*.md" -mmin -10

Modified in last 10 minutes.

Debugging Frontmatter Issues

Check for Invalid YAML

bash
head -20 "file.md" | grep -E "^[a-z_]+:"

Shows all frontmatter keys. Look for:

• Missing colons
• Inconsistent indentation
• Unexpected characters

Verify Frontmatter Values

bash
grep "^created:" "file.md"
grep "^slug:" "file.md"

Extract specific frontmatter fields.

Advanced (using yq):

bash
# Install: brew install yq
yq eval '.created' "file.md"

Parses YAML properly.

File Timestamp Types

Unix tracks three timestamps:

1. Modification Time (mtime)

When file content was last changed.

Check:

bash
stat -f "%Sm" "file.md"  # macOS
stat --format="%y" "file.md"  # Linux

2. Access Time (atime)

When file was last read.

Note: Often disabled on modern systems for performance.

3. Change Time (ctime)

When file metadata (permissions, ownership) changed.

macOS:

bash
stat -f "%Sc" "file.md"

Proving File Existence Order

Scenario: You want to prove File A existed before File B.

bash
ls -lt file-a.md file-b.md

Older file appears lower in output.

Or compare directly:

bash
if [ "file-a.md" -ot "file-b.md" ]; then
  echo "file-a.md is older"
else
  echo "file-b.md is older"
fi

Best Practices

1. Document Verification Steps

When testing, save your commands:

bash
# Create verification script
echo "ls -la _Nakul/TEST*.md" > verify.sh
echo "head -15 _Nakul/TEST*.md" >> verify.sh
chmod +x verify.sh

2. Use Absolute Paths

Avoid confusion:

bash
# Good
ls -la "/Users/you/vault/file.md"

# Bad (depends on current directory)
ls -la "file.md"

3. Capture Output for Records

bash
ls -la "file.md" > verification-$(date +%Y%m%d-%H%M%S).txt

Creates timestamped proof.

4. Check Before and After

Always verify state before making changes:

bash
# Before
ls -la "file.md"

# Make changes (AI edit, manual edit, etc.)

# After
ls -la "file.md"

Compare timestamps to confirm changes occurred.

Related Commands

Watch Directory for New Files

bash
# macOS
fswatch -0 /path/to/vault | xargs -0 -n1 echo "File changed:"

# Linux
inotifywait -m -r /path/to/vault

Count Files Created Today

bash
find . -name "*.md" -newermt "today" | wc -l

Find Files with Specific Frontmatter

bash
grep -l "^slug: xyz" *.md

Finds all files with slug: xyz.

Troubleshooting

Problem: stat command not found Solution: Use ls -l instead (less detailed but universal)

Problem: Timestamps don't match across systems Solution: Time zones! Convert to UTC or specify timezone explicitly

Problem: File appears in Obsidian but not terminal Solution: Check if Obsidian is showing a cached view; check file path carefully

Problem: Terminal shows file but Obsidian doesn't Solution: Refresh Obsidian vault (Cmd+R or restart)

Related

• Template Systems - Templater vs AI Agent Creation
• Managing Long Frontmatter