Mac iTerm多数命令提示Permission Denied，SSH公钥认证失败求助

Hey Corey, let's work through this permission denied problem together—this almost always boils down to misconfigured permissions on your ~/.ssh directory or the files inside it, since SSH has strict security rules about who can access these files. Here's how to diagnose and fix it:

Step 1: Check Current Permissions #

First, let's see what permissions are set on your .ssh folder and its contents. Run this command in your terminal:

ls -ld ~/.ssh && ls -l ~/.ssh

You'll see output showing permissions (like drwxr-xr-x for directories and -rw-r--r-- for files) plus the owner/group of each item.

SSH enforces these strict rules for security:

• Your ~/.ssh directory must have 700 permissions (only you can read/write/execute it)
• Your private key (e.g., id_rsa) must have 600 permissions (only you can read/write it—no one else can access it at all)
• Your public key (e.g., id_rsa.pub) can safely use 644 permissions (others can read it without risk)
• Auxiliary files like known_hosts should also be set to 600

Step 2: Fix Permissions #

If the permissions don't match the above, run these commands one by one to correct them:

# Lock down the .ssh directory to only your access
chmod 700 ~/.ssh

# Ensure private key is only readable/writable by you
chmod 600 ~/.ssh/id_rsa

# Set public key to allow read access for others (safe)
chmod 644 ~/.ssh/id_rsa.pub

# Fix known_hosts permissions if needed
chmod 600 ~/.ssh/known_hosts

Step 3: Verify File Ownership #

Sometimes even with correct permissions, files might be owned by another user (like root) instead of your account. Check the owner column in the ls -l ~/.ssh output—if it's not your username, run this to fix it:

chown -R $USER:$USER ~/.ssh

This recursively sets you as the owner of the .ssh directory and all its contents.

Why Regenerating Keys Didn't Help #

When you regenerated your keys, you probably created new files that inherited the same misconfigured permissions from the parent directory. SSH blocks access to keys if it detects that other users could potentially read your private key—this is a security feature, not a bug, so new keys won't fix the underlying permission issue.

Test the Fix #

After running the above commands, try your original actions again:

1. Run pbcopy < ~/.ssh/id_rsa.pub—it should no longer throw a permission error.
2. Attempt your SSH connection to the web application—this should resolve the permission denied (public key) error if permissions were the root cause.

If you still run into issues after this, feel free to share more details, but this fixes 90% of these kinds of SSH permission problems!

内容的提问来源于stack exchange，提问作者Corey