> ## Documentation Index > Fetch the complete documentation index at: https://help.freakhosting.com/llms.txt > Use this file to discover all available pages before exploring further. # chmod 755 Explained: Linux File Permissions, chmod and chown > chmod 755 explained: the owner can read, write and execute, everyone else can read and execute. Learn Linux permission numbers, chmod, chown and safe values. `chmod 755` gives the owner read, write and execute permission (7 = 4 + 2 + 1) and gives the group and everyone else read and execute (5 = 4 + 1). In `ls -l` it shows as `rwxr-xr-x`. Use 755 for directories and scripts, 644 (`rw-r--r--`) for normal files, and change the owner with `chown`, for example `sudo chown alex:www-data file`. | Difficulty | Time | Works on | Needs | | - | - | - | - | | Beginner | 10 minutes | Every Linux distribution | sudo for files you don't own | ## Before you start * [Connect with SSH](https://help.freakhosting.com/portals/other/how-to-connect-to-a-linux-server-with-ssh.md). You can change permissions on your own files; for other files you need `sudo` (root can leave it out). * Take a [backup or snapshot](https://help.freakhosting.com/portals/vps-panel/how-to-schedule-and-restore-backups.md) before you change permissions recursively on a large folder. ## How to read Linux permissions Run `ls -l`: ```bash theme={null} ls -l deploy.sh ``` ```text theme={null} -rwxr-xr-x 1 alex www-data 2048 Nov 4 13:27 deploy.sh ``` | Part | Meaning | | - | - | | `-` | Type: `-` file, `d` directory, `l` link | | `rwx` | **Owner** (`alex`) can read, write, execute | | `r-x` | **Group** (`www-data`) can read and execute | | `r-x` | **Others** (everyone else) can read and execute | Each letter has a number. Add them up for each of the three positions: | Letter | Number | On a file | On a directory | | - | - | - | - | | `r` read | 4 | Open and read it | List the names inside | | `w` write | 2 | Change it | Create, delete or rename files inside | | `x` execute | 1 | Run it as a program | Enter it (`cd`) and open files inside | ## What do chmod 755, 644, 600 and 777 mean? | Number | Letters | Owner | Group | Others | Typical use | | - | - | - | - | - | - | | `755` | `rwxr-xr-x` | all | read, execute | read, execute | Directories, scripts, programs | | `644` | `rw-r--r--` | read, write | read | read | Normal files, web pages | | `640` | `rw-r-----` | read, write | read | none | Config files with secrets read by a service group | | `600` | `rw-------` | read, write | none | none | Private keys, `authorized_keys` | | `700` | `rwx------` | all | none | none | `~/.ssh` and private folders | | `775` | `rwxrwxr-x` | all | all | read, execute | Shared group folders | | `777` | `rwxrwxrwx` | all | all | all | Avoid it | > [!WARNING] > > Don't "fix" a permission error with `chmod 777`. It lets every user and every process on the server change or replace the file, which is a common way websites get hacked. Find out which user needs access and give only that user or group the rights it needs. ## How to change permissions with chmod **1. Set permissions with numbers** ```bash theme={null} chmod 755 deploy.sh chmod 644 index.html ``` **2. Or change one part with letters** `u` = owner, `g` = group, `o` = others, `a` = all. `+` adds, `-` removes, `=` sets exactly. ```bash theme={null} chmod +x deploy.sh # make it executable for everyone chmod g+w report.csv # let the group write chmod o-rwx secrets.env # remove all rights for others chmod u=rw,go=r page.html # same as 644 ``` **3. Check the result** ```bash theme={null} stat -c '%A %a %n' deploy.sh ``` Expected output: ```text theme={null} -rwxr-xr-x 755 deploy.sh ``` ### How to set different permissions for files and directories `chmod -R 755` makes every file executable, which you rarely want. Use `find` to treat them separately, for example for a website: ```bash theme={null} sudo find /var/www/example.com -type d -exec chmod 755 {} + sudo find /var/www/example.com -type f -exec chmod 644 {} + ``` ## How to change the owner with chown ```bash theme={null} sudo chown alex report.csv # change owner sudo chown alex:www-data report.csv # change owner and group sudo chown :www-data report.csv # change only the group (or use chgrp) sudo chown -R alex:www-data /var/www/example.com # whole folder ``` The web server user is `www-data` on Ubuntu and Debian, and `nginx` or `apache` on AlmaLinux and Rocky Linux, depending on which web server you installed. > [!WARNING] > > Never run `chown -R` or `chmod -R` on `/`, `/etc`, `/usr` or `/var` as a whole. Changing system ownership breaks sudo, SSH and other services, and the only reliable fix is a [restore from backup](https://help.freakhosting.com/portals/vps-panel/how-to-schedule-and-restore-backups.md) or a reinstall. Double-check the path before pressing `Enter`. ## Special permissions: setgid and sticky bit | Bit | Number | Effect | Example | | - | - | - | - | | setgid on a directory | `2` | New files get the directory's group | `chmod 2775 /srv/shared` → `drwxrwsr-x` | | sticky bit on a directory | `1` | Users can only delete their own files (as in `/tmp`) | `chmod +t /srv/upload` → `drwxrwxrwt` | | setuid on a program | `4` | Runs as the file's owner | Used by `passwd`; don't set it on your own scripts | ## What is umask? `umask` sets the default permissions for new files. The usual value `0022` makes new files `644` and new directories `755`. Check yours with `umask`. ## How to check it worked Test as the user who needs access, for example the web server user: ```bash theme={null} sudo -u www-data cat /var/www/example.com/index.html ``` If the file prints, the permissions are right. `Permission denied` means the user is missing `r` on the file or `x` on one of the parent directories. `namei -l /var/www/example.com/index.html` shows the permissions of every directory in the path. ## Frequently asked questions ### What is the difference between chmod 755 and 644? 755 adds execute (`x`). Directories need `x` so you can open them, and scripts need it to run. Plain files such as HTML, images and config files don't, so they use 644. ### What permissions should `~/.ssh` have? `~/.ssh` must be `700` and `~/.ssh/authorized_keys` `600`, owned by the user. SSH refuses keys when they are more open. See [fix SSH "Permission denied (publickey)"](https://help.freakhosting.com/portals/other/how-to-fix-ssh-permission-denied-publickey.md). ### What does chmod +x do? It adds execute permission for the owner, group and others (limited by your umask), so you can run the file with `./script.sh`. ### Why does chmod say "Operation not permitted"? Only the owner or root can change a file's permissions. Use `sudo`, or check the owner with `ls -l`. ## Related guides > [card] [VPS and dedicated server guides](https://help.freakhosting.com/portals/other/vps-and-dedicated-server-guides.md) > > Every server guide in one place. > [card] [Manage users and groups](https://help.freakhosting.com/portals/other/how-to-manage-users-and-groups-on-linux.md) > > Put users in shared groups. > [card] [Essential Linux commands](https://help.freakhosting.com/portals/other/essential-linux-commands-for-server-beginners.md) > > The commands you use every day. > [card] [Find files and text](https://help.freakhosting.com/portals/other/how-to-find-files-and-text-on-linux.md) > > Search with find and grep. *** > [!NOTE] > > **Checked against the official [GNU Coreutils manual: chmod, chown and file modes](https://www.gnu.org/software/coreutils/manual/html_node/File-permissions.html)** on 4 November 2026; commands tested on Ubuntu 24.04 LTS. Commands can differ on other distributions or releases. > [!NOTE] > > ### Need Extra Help? > > If you encounter any issues, our support team is ready to assist: > > * **Live Chat:** Quick assistance via our website. > * **Support Ticket:** [Open a Ticket](https://freakhosting.com/clientarea/submitticket.php) > * **Discord:** [Join our Community](https://discord.gg/freakhosting) > * **Email:** [support@freakhosting.com](mailto:support@freakhosting.com) > [!TIP] > > ### Save on Your Hosting > > Ready to upgrade your hosting? Use code **KB20** at checkout for **20% off** your first order! *** **Last Updated:** November 2026 This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.