chmod Calculator
Calculate Unix/Linux chmod permission values. Toggle read/write/execute permissions for owner, group, and others. Get both octal and symbolic notation instantly.
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Smart PicksHow to use chmod Calculator
chmod Calculator converts between human-readable permission checkboxes and Unix octal/symbolic notation. Essential for server administration and Linux development.
- 1Check the permissions you want for Owner, Group, and Others.
- 2See the octal value (e.g., 755) update instantly.
- 3Read the symbolic notation (e.g., rwxr-xr-x) in the output.
- 4Or enter an octal value directly to see what permissions it represents.
- 5Copy the chmod command (e.g., chmod 755) ready to paste in terminal.
Common Use Cases
- Setting correct permissions for web server files and directories
- Configuring SSH key file permissions (chmod 600 ~/.ssh/id_rsa)
- Making shell scripts executable (chmod +x script.sh)
- Troubleshooting 403 Forbidden errors caused by wrong file permissions
Pro Tips
- Directories usually need execute permission (x) to be accessible โ use 755 for public dirs.
- SSH private keys must be 600 (owner read/write only) or SSH will refuse them.
- Use 644 for regular web files, 755 for directories and scripts.
- The sticky bit (chmod +t) prevents users from deleting others' files in shared directories.
Frequently Asked Questions
chmod (change mode) is a Unix command that changes file and directory permissions. Permissions control who can read, write, or execute a file.
755 means: Owner can read, write, execute (7=rwx). Group can read and execute (5=r-x). Others can read and execute (5=r-x). This is typical for web server directories.
644 means: Owner can read and write (6=rw-). Group can only read (4=r--). Others can only read (4=r--). This is standard for web files.
Symbolic notation uses letters: r=read, w=write, x=execute, with - for no permission. Example: rwxr-xr-x = 755.
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