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Who Can Open What

Linux decides who can open a file using nine characters. Read them once properly and you never have to guess whether a file is private.

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Commands practised here

• chmod 644 fileOwner reads and writes, everyone else reads.
• chmod 600 fileOnly the owner. Use this for anything secret.
• chmod 755 scriptEveryone can run it. Normal for scripts.
• ls -lShows the permission string for every file.

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