Fix permissions on Mac for Midnight Commander install by Brew

Overview

Midnight Commander (mc) is a visual file manager for Unix-like systems that provides a dual-pane interface similar to Norton Commander. On macOS, permission conflicts commonly arise when mc attempts to write to XDG Base Directory specification paths (~/.config, ~/.local/share, ~/.cache) that were created by other processes or during system migrations.

Understanding the Permission Model

macOS combines traditional POSIX permissions (user/group/other rwx) with ACLs (Access Control Lists) and System Integrity Protection (SIP). When Midnight Commander runs, it needs:

• Read/Write access to ~/.config/mc/ for configuration files (ini, panels)
• Write access to ~/.local/share/mc/ for command history and hotlist
• Write access to ~/.cache/mc/ for temporary files and thumbnails

Permission issues typically manifest as:

• Cannot write to ~/.config/mc/ini errors
• Loss of panel history between sessions
• Command history not persisting
• Exit code 1 without clear error messages

Common root causes:

1. UID mismatch: Directories created by sudo operations (owned by root:wheel)
2. Migration artifacts: Files from Time Machine restore with incorrect ownership
3. Shared system use: Multiple admin users creating conflicting ownership
4. ACL overrides: Extended attributes taking precedence over POSIX bits

Install Midnight Commander via Homebrew

1brew install midnight-commander

Fix Permissions Issues

1sudo chown -R $(whoami) /Users/$(whoami)/.local
2sudo chown -R $(whoami) /Users/$(whoami)/.cache
3sudo chown -R $(whoami) /Users/$(whoami)/.config

Why this happens

Homebrew installs Midnight Commander into /opt/homebrew (Apple Silicon) or /usr/local (Intel) and expects your user to own the config and cache paths that mc writes to. If these directories were created by another UID (migration, sudo, Time Machine restore), mc cannot write its history or panels state, so it exits with permission errors. The chown commands above restore ownership so mc can persist its runtime files.

Technical Deep Dive: XDG Base Directory Specification

Midnight Commander follows the XDG Base Directory specification for locating configuration and data files:

Understanding the Output

The ls -le output includes extended attributes marked with @ and ACLs marked with +:

The + suffix indicates ACL presence. The stat command shows numeric UID/GID and symbolic mode.

Common ACL entries on macOS:

• group:everyone deny delete - prevents accidental deletion
• user:root allow list,search,readattr - allows system processes to read
• group:wheel allow read - admin group read access

If you see unknown ACL entries, you can drop them (use cautiously):

1chmod -RN ~/.local ~/.cache ~/.config

Alternative: Surgical ACL Removal

Instead of removing all ACLs, target specific entries:

1# List all ACLs in detail
2ls -led ~/.config/mc
3
4# Remove specific ACL entry (example: removing entry 0)
5chmod -a# 0 ~/.config/mc
6
7# Add explicit user permission via ACL (if needed)
8chmod +a "user:$(whoami) allow read,write,execute,delete,append,readattr,writeattr,readextattr,writeextattr" ~/.config/mc
9
10```bash
11# Example of correct ownership (user owns, group=staff)
12drwxr-xr-x   5 username  staff   160 Feb  1 10:30 .config
13
14# Problematic state after sudo operation (root owns)
15drwxr--prefix
16brew list --versions midnight-commander

Interpreting Homebrew Paths

Apple Silicon Macs (M1/M2/M3/M4):

• Homebrew prefix: /opt/homebrew
• Binaries: /opt/homebrew/bin/mc
• Cellar location: /opt/homebrew/Cellar/midnight-commander/VERSION

Intel Macs:

What This Command Does

diskutil resetUserPermissions performs a comprehensive ownership reset:

1. Recursively walks /Users/username and all subdirectories
2. Resets ownership of all files to match the UID provided
3. Preserves group membership (typically staff)
4. Fixes ACLs by removing inherited entries that conflict with POSIX

Advanced Configuration Management

For persistent configuration across shell sessions, add to your shell profile:

1# ~/.zshrc or ~/.bashrc
2export MC_CONFIG_DIR="$HOME/dotfiles/mc/config"
3export MC_DATA_DIR="$HOME/dotfiles/mc/data"
4export MC_CACHE_DIR="$HOME/.cache/mc"
5
6# Optional: create directories if they don't exist
7[[ ! -d "$MC_CONFIG_DIR" ]] && mkdir -p "$MC_CONFIG_DIR"
8[[ ! -d "$MC_DATA_DIR" ]] && mkdir -p "$MC_DATA_DIR"

Environment Variables Reference

Midnight Commander respects these environment variables (in order of precedence):

Symlinking Configuration for Version Control

Keep mc configuration in a git-tracked dotfiles repository:

1# Assuming dotfiles repo at ~/dotfiles
2mkdir -p ~/dotfiles/mc/config ~/dotfiles/mc/data
3
4# Backup existing config
5[[ -d ~/.config/mc ]] && cp -r ~/.config/mc ~/.config/mc.backup
6
7# Create symlinks
8ln -sf ~/dotfiles/mc/config ~/.config/mc
9ln -sf ~/dotfiles/mc/data ~/.local/share/mc
10
11# Add to git
12cd ~/dotfiles
13git add mc/
14git commit -m "Add Midnight Commander configuration"

Debugging Configuration Loading

Verify which config files mc is actually reading:

1# Launch mc with profiling to see file access
2MC_PROFILE_ENABLED=1 mc 2>&1 | grep "config"
3
4# Or use fs_usage (requires sudo, generates lots of output)
5sudo fs_usage -f filesys -w mc | grep -E "(config|ini|panels)"

Sample Configuration Files

~/.config/mc/ini (key bindings and settings):

1[Midnight-Commander]
2use_internal_edit=true
3use_internal_view=true
4auto_save_setup=true
5preallocate_space=false
6auto_menu=false
7drop_menus=false
8shell_patterns=true
9confirm_delete=true
10confirm_overwrite=true

~/.config/mc/panels.ini (panel layout):

1[New Left Panel]
2display=listing
3reverse=false
4case_sensitive=true
5exec_first=false
6
7[New Right Panel]
8display=listing
9reverse=false
10case_sensitive=true
11exec_first=false

Verification and Testing

After applying permission fixes, verify mc works correctly:

1# Test basic launch
2mc --version && echo "MC binary accessible"
3
4# Test config write
5mc -F 2>&1 | grep -i "permission\|error" || echo "No permission errors"
6
7# Check runtime files exist
8ls -la ~/.config/mc/ ~/.local/share/mc/
9
10# Test history persistence
11mc -c "cd /tmp && exit"
12grep -q "/tmp" ~/.local/share/mc/history 2>/dev/null && echo "History persisted successfully"

Prevention: Best Practices

1. Avoid using sudo for home directory operations

   bash

   Copy

   1# ❌ Wrong - creates root-owned files
   2sudo vim ~/.config/myapp/config.ini
   3
   4# ✅ Correct - regular user
   5vim ~/.config/myapp/config.ini

2. Set correct umask to ensure new files have proper permissions:

   bash

   Copy

   1# Add to ~/.zshrc or ~/.bashrc
   2umask 022  # New files: rw-r--r--, directories: rwxr-xr-x

3. Use Time Machine backup carefully - restore to same username when possible

4. Regular permission audits:

   bash

   Copy

   1# Weekly check for root-owned files in home directory
   2find ~ -user root -ls 2>/dev/null | grep -v "/Library/"

Related Issues and Resources

• macOS SIP documentation: man csrutil
• Homebrew troubleshooting: brew doctor output explanation at docs.brew.sh
• XDG Base Directory spec: specifications.freedesktop.org/basedir-spec
• Midnight Commander documentation: /opt/homebrew/share/doc/mc/ or man mc

Common Error Messages and Solutions

| Error Message | Root Cause | Solution | | ---------------------------------- | ---------------------- | ----------------------------------------- | -------------------------------------------------------------------------- | | Cannot write to ~/.config/mc/ini | Wrong ownership | chown -R $(whoami) ~/.config | | Permission denied on panel save | ACL blocking write | chmod -RN ~/.config/mc | | No such file or directory | Missing XDG dirs | mkdir -p ~/.config/mc ~/.local/share/mc | | mc exits immediately with code 1 | Cache dir not writable | chown -R $(whoami) ~/.cache | Respects SIP-protected paths like ~/Library/Saved Application State/ |

Timing: On a 500GB home directory, expect 10-30 minutes. The operation is non-destructive to file contents but modifies metadata.

When to use:

• After restoring from Time Machine backup
• After system migration or disk clone
• When multiple applications report permission errors
• If sudo was used extensively for home directory operations

Warning signs indicating you need this:

1# Multiple apps cannot write to home directory
2touch ~/test.txt
3# Permission denied
4
5# Even new files show wrong ownership
6ls -l ~/test.txt
7# -rw-r--r--  1 root  staff  0 Feb  1 10:30 test.txt

SIP (System Integrity Protection) Considerations

If the command fails with "Operation not permitted," SIP may be blocking it. Check SIP status:

1csrutil status
2# System Integrity Protection status: enabled.

To run diskutil resetUserPermissions with SIP enabled:

1. Reboot into Recovery Mode (hold Cmd+R on Intel, hold Power on Apple Silicon)
2. Open Terminal from Utilities menu
3. Mount your volume (if not auto-mounted):
   bash

   Copy

   1diskutil list
   2diskutil mount disk1s1  # adjust disk identifier

4. Run the reset:
   bash

   Copy

   1diskutil resetUserPermissions /Volumes/Macintosh\ HD $(dscl /Volumes/Macintosh\ HD/var/db/dslocal/nodes/Default -read /Users/username UniqueID | awk '{print $2}')

5. Reboot normally

Do not disable SIP unless absolutely necessary, as it protects critical system files.

• Homebrew prefix: /usr/local
• Binaries: /usr/local/bin/mc
• Cellar location: /usr/local/Cellar/midnight-commander/VERSION

Verify mc is in your PATH:

1which mc
2# Should output: /opt/homebrew/bin/mc (Apple Silicon) or /usr/local/bin/mc (Intel)
3
4# Check if mc can see its own info
5mc --version

Troubleshooting Multiple Homebrew Installations

If you've migrated from Intel to Apple Silicon or have both installations:

1# List all mc binaries
2find /usr/local /opt/homebrew -name mc -type f 2>/dev/null
3
4# Check PATH precedence
5echo $PATH | tr ':' '\n' | nl
6
7# Force use of specific installation
8/opt/homebrew/bin/mc  # Apple Silicon
9/usr/local/bin/mc     # Intelb  1 10:30 .config
10
11# Mixed ownership (parent OK, child broken)
12drwxr-xr-x   5 username  staff   160 Feb  1 10:30 .config
13drwxr-xr-x   3 root      wheel    96 Feb  1 10:31 .config/mc

The chown -R recursive flag ensures all subdirectories and files inherit correct ownership.

Check current ownership and ACLs

Run a quick inspection before and after the fix to confirm ownership and to spot unexpected ACL entries that may override POSIX permissions:

1ls -le ~/.local ~/.cache ~/.config
2stat -f "%N uid=%u gid=%g mode=%Sp" ~/.local ~/.cache ~/.config

If you see unknown ACL entries, you can drop them (use cautiously):

1chmod -RN ~/.local ~/.cache ~/.config

Homebrew health check

Ensure your Homebrew prefix and environment are consistent, and that mc is installed where you expect:

1brew doctor
2brew --prefix midnight-commander
3brew list --versions midnight-commander

Last-resort: reset user permissions on the volume

When multiple apps show similar home-directory permission issues, reset your account permissions on the system volume (macOS 10.13+):

1sudo diskutil resetUserPermissions / $(id -u)

Run it from Recovery if SIP blocks the command. Afterward, re-run the chown steps above for your dot-directories.

Optional: isolate Midnight Commander config

If you prefer to keep mc config in a dedicated path (e.g., inside a synced dotfiles repo), point MC_CONFIG_DIR and MC_DATA_DIR before launching:

1export MC_CONFIG_DIR="$HOME/.config/mc"
2export MC_DATA_DIR="$HOME/.local/share/mc"
3mc