How to fix fatal: could not create work tree dir 'repo': Permission denied in Git

First, verify where you're trying to clone and whether you have write permissions:

pwd
ls -la .

Look at the output - if the directory is owned by root or another user, that's your problem:

drwxr-xr-x  5 root root  4096 Jan 15 10:00 .

The r-x for others (the last three characters) means you can read and execute but not write.

The simplest solution is to clone to a directory you own:

cd ~
git clone https://github.com/username/repo.git

Or specify a full path within your home directory:

git clone https://github.com/username/repo.git ~/projects/repo

You can also create a dedicated projects directory:

mkdir -p ~/projects
cd ~/projects
git clone https://github.com/username/repo.git

If you need to clone to a specific location outside your home directory, create it first with appropriate ownership:

# Create the directory with sudo
sudo mkdir -p /opt/projects

# Change ownership to your user
sudo chown $USER:$USER /opt/projects

# Now clone works without sudo
git clone https://github.com/username/repo.git /opt/projects/repo

Important: Don't run git clone itself with sudo - this creates a repository owned by root, causing permission issues later.

If your home directory ownership was accidentally changed, fix it:

# Check home directory ownership
ls -la ~

# If owned by root, fix it
sudo chown -R $USER:$USER ~

This can happen if you've run commands like sudo git clone or sudo npm install in your home directory.

Warning: Be careful with recursive chown in ~ if you have special files or directories with intentionally different ownership.

Permission denied errors can sometimes mask disk-full conditions:

# Check available disk space
df -h .

# Check if filesystem is read-only
mount | grep "$(df . | tail -1 | awk '{print $1}')"

If the disk is full:

# Find large files
du -sh /* 2>/dev/null | sort -h | tail -20

# Clear package manager cache
sudo apt clean        # Debian/Ubuntu
sudo yum clean all    # RHEL/CentOS

If the filesystem is mounted read-only (ro), remount it:

sudo mount -o remount,rw /mountpoint

For NFS or CIFS mounted directories, check mount options:

mount | grep nfs
mount | grep cifs

Common fixes for NFS:

# Remount with proper options (edit /etc/fstab for persistence)
sudo mount -o remount,rw,user /nfs/share

For CIFS/SMB shares, ensure proper credentials and permissions:

# Mount with your user/group IDs
sudo mount -t cifs //server/share /mnt/share -o username=you,uid=$(id -u),gid=$(id -g)

Contact your system administrator if you're on a managed system and can't modify mount options.