log Git Command Guide

The git log command displays the commit logs for a repository, showing commit information in reverse chronological order. It provides comprehensive history browsing with formatting options, filtering capabilities, and detailed commit information display.

git log Syntax:

git log [<options>] [<revision-range>] [[--] <path>...]

Display Options:

Option	Description
--oneline	Condensed format: abbreviated hash and title
--short	Shorter format than default
--full	Full format (default)
--fuller	Even more information
--raw	Show raw commit information
--graph	Display ASCII graph of branch structure
`—decorate[=short	full
--stat	Show diff statistics
--numstat	Show numeric diff statistics
--shortstat	Show summary of changes
--name-only	Show only names of changed files
--name-status	Show names and status of changed files

Limiting Options:

Option	Description
-<n>	Show only last n commits
--since=<date>	Show commits more recent than date
--until=<date>	Show commits older than date
--author=<pattern>	Show commits by authors matching pattern
--committer=<pattern>	Show commits by committers matching pattern
--grep=<pattern>	Show commits with messages matching pattern
--all-match	Show only commits matching all —grep
--invert-grep	Show commits not matching —grep
-S<string>	Show commits changing the number of occurrences
-G<regex>	Show commits whose diff matches regex
--follow	Follow file renames
--no-merges	Don’t show merge commits
--merges	Show only merge commits
--first-parent	Follow only first parent of merges
--not	Reverse the meaning of ^ prefix
--all	Show all refs

Formatting Options:

Option	Description
--pretty=<format>	Pretty-print with format
--format=<format>	Alias for —pretty=format
--abbrev-commit	Show abbreviated commit hash
--no-abbrev-commit	Don’t abbreviate hash
--oneline	Shortcut for —pretty=oneline —abbrev-commit
--encoding=<encoding>	Re-encode commits to encoding

Parameters:

Parameter	Description
<revision-range>	Range of commits to show (e.g., master..feature)
<path>...	Show only commits affecting these paths

Basic Usage Examples:

View Recent Commits:

# Show recent commits in default format
git log

# Show last 5 commits
git log -5

# Show commits in compact format
git log --oneline

Graph Visualization:

# Show branch structure with graph
git log --oneline --graph --all

# View merge history
git log --graph --oneline --first-parent

Time-Based Filtering:

# Commits from last week
git log --since="1 week ago"

# Commits from specific date range
git log --since="2023-01-01" --until="2023-12-31"

# Commits by date with author
git log --since="2 months ago" --author="John"

Content Filtering:

# Commits mentioning specific text
git log --grep="fix"

# Case-insensitive search
git log --grep="FIX" -i

# Commits by author pattern
git log --author=".*@company.com"

Path-Specific History:

# Commits affecting specific file
git log --follow -- src/main.c

# Commits in directory
git log -- src/

# Multiple files
git log -- README.md CHANGELOG.md

Advanced Formatting:

Custom Pretty Formats:

# Custom format
git log --pretty=format:"%h %s %d"

# Full custom format
git log --pretty=format:'%C(yellow)%h%Creset %Cgreen%ad%Creset %s %Cblue%an%Creset %Cred%d%Creset' --date=short

# Include trailers
git log --pretty=format:"%h %s%n%(trailers:unfold,key=Signed-off-by,valueonly)"

Differential Statistics:

# Show file changes summary
git log --stat

# Show numerical statistics only
git log --numstat

# Overall statistics
git log --shortstat

Branch and Tag Analysis:

# Show all references
git log --oneline --all --graph

# Compare branches
git log --oneline master..feature-branch

# Find branching point
git log --oneline --merges master

Specialized Queries:

Author and Committer Analysis:

# Detailed author information
git log --format='%aN <%aE>' | sort | uniq -c | sort -rn

# Committer vs author differences
git log --format='%an vs %cn' --all-match --grep="Co-authored-by"

# Recent contributors
git log --since="6 months ago" --format='%aN' | sort | uniq

Message Pattern Analysis:

# Commits starting with certain patterns
git log --grep="^feat\|fix\|docs\|style\|refactor\|test\|chore" --oneline

# Breaking changes
git log --grep="BREAKING\|breaking" --oneline

# Issue tracker links
git log --grep="#[0-9]\+" --oneline

Change Type Analysis:

# Only merge commits
git log --merges --oneline

# Exclude merges
git log --no-merges --oneline

# First parent path (main branch development)
git log --first-parent --oneline

Practical Workflow Examples:

Code Review Preparation:

# See changes for review
git log --oneline --stat origin/main..HEAD

# Detailed diff for reviewer
git log -p --reverse origin/main..HEAD

# Summary for release notes
git log --oneline --grep="feat\|fix\|docs" origin/v1.0..HEAD

Bug Investigation:

# Find commits affecting file around date
git log --since="2023-01-01" --until="2023-01-31" -- src/file.c

# Find commits changing specific string
git log -S"bug" --oneline

# Find commit introducing regex pattern
git log -G"TODO|FIXME" --oneline

Release Management:

# Generate changelog
git log --oneline --format="* %s (%h)" v1.0..HEAD

# Version bump commits only
git log --grep="bump\|version\|release" --oneline

# Feature additions since release
git log --grep="^feat" --oneline tag/v1.0.0..HEAD

Repository Analysis:

# Most active contributors
git log --format='%aN' | sort | uniq -c | sort -nr | head -10

# Commits by week
git log --date=short --format='%ad' | cut -d- -f1-2 | sort | uniq -c

# Productivity metrics (commits per day)
git log --date=short --format='%ad' | sort | uniq -c | awk '{print $2 ": " $1 " commits"}'

Performance Optimization:

Large Repository Handling:

# Limit depth for speed
git log --oneline -100

# Specific time range for analysis
git log --since="3 months ago" --oneline

# Path-limited search
git log -- src/lib/ --oneline

Pipeline Optimization:

# Efficient author searching
git log --format='%H %aE %aN' --all | awk '/@company.com/ {print $1}' | xargs git show --stat

# Batch processing commits
git log --format='%H' --oneline | head -50 | xargs -I {} sh -c 'git show --name-only {} | head -20'

Integration Examples:

With External Tools:

# Export for project management
git log --format='%H|%an|%ae|%s|%(trailers:key=Fixes,valueonly)' > commits.csv

# Feed to ticket system
git log --grep="#[0-9]\+" --format='%H %s' | while read hash msg; do
    ticket=$(echo "$msg" | grep -o '#[0-9]\+')
    echo "Commit $hash affects ticket $ticket"
done

CI/CD Integration:

#!/bin/bash
# Generate deployment notes
git log --oneline --format="* %s (%aN)" origin/main..HEAD > deploy-notes.txt

# Validate commit standards
if ! git log --format='%s' -1 | grep -q "^(feat|fix|docs|style|refactor|test|chore):"; then
    echo "Commit message doesn't follow conventional commits"
    exit 1
fi

Formatting and Display Customization:

Color Customization:

# Colored output
git log --color --oneline

# Configure colors
git config color.log.date yellow
git config color.log.author blue

Terminal Pagination:

# Configure pager
git config core.pager "less -FRSX"
git config pager.log "true"

# Disable pagination for scripts
git --no-pager log --oneline | head -10

Troubleshooting:

Empty Log Output:

# Check if in repository
git status

# Check current branch commits
git log --oneline HEAD

# See all branches
git log --all --oneline | head -10

Performance Issues:

# Time-consuming operations
time git log --all --graph

# Optimize with caching
git config core.logAllRefUpdates true

Encoding Problems:

# Fix character encoding
git log --encoding=UTF-8

# Configure repository encoding
git config i18n.logOutputEncoding UTF-8

Path Resolution Issues:

# Verify file exists in history
git log --follow -- missing-file.txt 2>/dev/null || echo "File not in history"

# Check case sensitivity
git log --follow -- 'path/file.txt'

Caution

git log can show sensitive information. Use —all flag carefully in shared environments. Large repositories may require limiting options for performance.

How does git log —graph work?

Creates ASCII visualization of commit ancestry, showing branches, merges, and commit relationships through text characters connecting related commits.

What’s the difference between —stat and —shortstat?

—stat shows per-file statistics with +/- counts; —shortstat shows only repository-level summary (files changed, insertions, deletions).

Why use —first-parent?

Follows only first parent of merges, showing mainline development while hiding merged feature branches - useful for understanding deployment timeline.

How do trailers work with git log?

Use %(trailers) format specifier to display or process commit message trailers separately from main commit message.

What’s the performance cost of —follow?

Follows file renames across entire repository history - expensive for large repos, suitable for single file analysis only.

Can git log show binary file changes?

Shows file was modified but doesn’t display binary diff. Use —name-only to see which binaries changed without content display.

How does —reverse work?

Reverses normal chronological order, showing oldest commits first - useful for recreating development timeline or chronological analysis.

What’s the difference between —author and —committer?

Author is who wrote the code, committer is who created the commit. Different in patch workflows where someone applies another’s changes.

Can git log filter by file type?

Yes, combine with path patterns: git log — ‘.c’ ‘.h’ for only C source files, or use —name-only with grep for post-filtering.

How do I see only commits changing specific lines?

Use git log -L ,: to show changes to specific line range. Shows commits affecting specified lines in the file.

What’s the —ancestry-path option?

Shows commits reachable from but not from while maintaining path between commits - useful for complex merge analysis.

How do reflog vs log differ?

git log shows committed history; git reflog shows local reference changes including resets, rebases, amendments - broader than permanent history.

Applications of the git log command

1. Development Monitoring: Track code evolution and contributor activity over time
2. Bug Investigation: Trace when bugs were introduced and through which commit paths
3. Code Review Facilitation: Prepare comprehensive change summaries for review teams
4. Release Preparation: Generate changelogs and validate release candidate contents
5. Team Collaboration: Share repository history and coordinate development activities
6. Compliance Auditing: Verify change history for regulatory and quality requirements