Free chmod Calculator
Toggle read/write/execute for owner, group, and others · and get the octal and symbolic chmod notation both ways.
Frequently asked
What do 755 and 644 mean?
Each digit is owner/group/others, summing read=4, write=2, execute=1. 755 = rwxr-xr-x (directories, executables); 644 = rw-r--r-- (regular files). Directories need execute to be entered · that's why files and dirs differ.
When is 777 a problem?
Almost always · it lets any local user or compromised process modify the file. World-writable web roots turn any minor breach into persistent code execution. If something "only works with 777", fix ownership instead.
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