T*he execute bit allows the affected user to enter it and access and change file and directory attributes and directories inside.* permission to execute other filesystem linux commands may need to be "executed" on sub-directories and files is determined by "execute bit". Not to be confused with executing an executable file, it means you have given "executive decision-making" privvies to edit the links to inode file numbers or metadata associated with filenames and symbolic links.
Variations of features include Execute with write disabled. meaning you can rename a file but not edit the contents. Or write enabled but execute disabled visa versa.
"Each disk drive contains some number of file systems. A file system consists of a number of cylinder groups. Each cylinder group has inodes and
A file system is described by its super-block, which in turn describes
the cylinder groups. The super-block is critical data and is replicated
in each cylinder group to protect against catastrophic loss. This is
done at file system creation time and the critical super-block data does
not change, so the copies need not be referenced further unless disaster
Addresses stored in inodes are capable of addressing fragments of
`blocks'. File system blocks of at most size MAXBSIZE can be optionally
broken into 2, 4, or 8 pieces, each of which is addressable; these pieces
may be DEV_BSIZE, or some multiple of a DEV_BSIZE unit."
Other interesting details;
" If you have execute (but not write) permission on a directory AND you have write permission on a file living within, you cannot delete the file (because it involves removing it from the list). However, you can erase its contents e.g. if it's a text file you can use vi to open it and delete everything. The file will still be there, but it will be empty." ...Baldrick
stat -f "%Sp -> owner=%SHp group=%SMp other=%SLp" to display ACL stats