When attempting to update an existing symbolic link using ln -f -s, you might encounter situations where the command appears to execute without errors, yet the symlink target remains unchanged. This typically happens when:

• The destination path contains spaces or special characters
• Permissions prevent modification of the symlink's parent directory
• The command is executed in the wrong working directory

Here are three proven methods to update a symbolic link target:

Method 1: Using ln with Proper Syntax

# Correct order: new target first, then link name
ln -sfn /var/www/html/releases/build1390 app-current

The -n flag (no-dereference) is crucial when updating symlinks that might point to directories.

Method 2: Atomic Update with mv

# Create new symlink with temporary name
ln -s /var/www/html/releases/build1390 app-current.tmp
# Atomically replace old symlink
mv -f app-current.tmp app-current

Method 3: Using GNU coreutils (modern systems)

# Force create or update symlink
ln -sf -- /var/www/html/releases/build1390 app-current

If the above methods still don't work, check these potential issues:

Filesystem Mount Constraints

Some mounted filesystems (particularly network shares) may restrict symlink operations. Try:

mount | grep "app-current"

POSIX vs GNU ln Behavior

Different Unix variants handle symlink updates differently. For maximum compatibility:

# BSD/macOS compatible version
ln -sfh /var/www/html/releases/build1390 app-current

Here's a complete deployment script pattern we use in production:

#!/bin/bash
RELEASE_DIR="/var/www/html/releases/build$(date +%s)"
CURRENT_LINK="/var/www/html/app-current"

# Create new release
mkdir -p "$RELEASE_DIR"
# (deployment steps here...)

# Update symlink - using atomic method
ln -sfn "$RELEASE_DIR" "$CURRENT_LINK.tmp"
mv -f "$CURRENT_LINK.tmp" "$CURRENT_LINK"

# Verify update
if [ "$(readlink -f "$CURRENT_LINK")" != "$(readlink -f "$RELEASE_DIR")" ]; then
    echo "Symlink update failed!" >&2
    exit 1
fi

---

Many developers encounter this frustrating scenario when deploying applications with symlinks:

ln -f -s /var/www/html/releases/build1390 app-current
# No error appears, but the symlink target remains unchanged

The standard force flag (-f) in ln may fail when:

• The symlink has special permissions
• The parent directory has restrictive permissions
• The target is on a different filesystem
• There are filesystem caching issues

Method 1: Remove and Recreate (Most Reliable)

rm app-current && ln -s /var/www/html/releases/build1390 app-current

Method 2: Use ln with -n Flag

ln -sfn /var/www/html/releases/build1390 app-current

The -n (--no-dereference) treats the symlink itself as the file to modify.

Method 3: Atomic Update with mv

ln -s /var/www/html/releases/build1390 app-current.tmp \
&& mv -fT app-current.tmp app-current

On NFS-mounted directories, you might need additional steps:

unlink app-current
ln -s /var/www/html/releases/build1390 app-current

Here's how we handle symlink updates in our deployment scripts:

#!/bin/bash
NEW_BUILD="/var/www/html/releases/build${BUILD_NUMBER}"
OLD_LINK="/var/www/html/app-current"

# Safely update symlink
ln -snf "$NEW_BUILD" "$OLD_LINK" || {
    echo "Failed to update symlink, trying alternative method" >&2
    rm -f "$OLD_LINK" && ln -s "$NEW_BUILD" "$OLD_LINK"
}

When symlinks misbehave:

# Check symlink status
ls -l app-current
stat app-current

# Verify filesystem type
df -Th $(dirname app-current)

# Check for filesystem mount options
mount | grep $(df -P app-current | tail -1 | cut -d' ' -f1)