Unix file permissions without the headache: tick read, write and execute for user, group and others, and get the octal mode, symbolic notation and the exact chmod command.
User
Group
Others
Octal
Symbolic
rw-r--r--
Meaning
Command
chmod 644 filename
What the tool does
Every Unix file has nine permission bits: read, write and execute for the owner, the group and everyone else. Tick the boxes and the tool shows the octal number (like 644), the symbolic string (like rw-r--r--), a plain-words description, and the chmod command to apply it.
Worked example
A typical web file is 644 (rw-r--r--): the owner can read and write, everyone else can only read. A script you run is 755 (rwxr-xr-x): everyone can read and execute, only the owner can write.
Common modes
644 for files, 755 for directories and scripts, 600 for private files like SSH keys (owner read/write only). Avoid 777: it gives everyone full control and is a security hole.
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Frequently asked questions
What do the octal numbers mean?
Each digit is one class: user, group, others. Read is 4, write is 2, execute is 1; add them up. So 7 means read+write+execute, 6 means read+write, 4 means read-only.
What is the difference between 644 and 755?
644 (rw-r--r--) is standard for files: nobody gets execute. 755 (rwxr-xr-x) adds execute for everyone, used for directories (needed to list them) and scripts.
Why is 777 dangerous?
It grants read, write and execute to literally everyone on the system. Any compromised account or process can then modify or replace the file.
Does this change my files?
No. The tool only computes the values and shows the command. Run the chmod command yourself on your own machine.