• -rwxr-x---
  • In symbolic mode, a value is assigned to each position and presents a symbolic representation of the desired permissions.
    • For example u=rwx
    • No math involved unlinke numeric mode.
  • For example, to specify rwx for the User Owner.
    • This would be u=rwx
  • For r-x for the Group Owner:
    • g=rx
  • To set --- for Other:
    • o=
      • There is intentionally nothing after the =
  • To set multple permissions at once, separate them with a comma –> chmod u=rwx,g=rx,o= file.txt
  • Can also add permissions by changing the = into a +
    • chmod u+rwx file.txt
      • Adds rwx to a user.
  • To subtract permissions, replace with a - sign.
    • chmod u-x file.txt
    • To take execute permissions away from Other, this would be chmod o-x file.txt
  • How to add multiplep permissions at once:
    • chmod u=rwx,g=rx,o= file.txt
      • More typing, but easier to understand.
        • To add or take away permission, in numeric mode we would have to know the initial permissions and then re-calculate accordingly.
  • Can add and subtract permissions in symbolic mode.
  • Remove execute permissions from the group chmod g-x file.txt
  • Can also remove individual permissions per Owner:
    • chmod ugo-x file.txt
  • Can specify a for all positions, includes User Owner, Group Owner and Other.
    • chmod a-x file.tx
  • To remove execute permissions for every file in a user’s home directory:
    • sudo chmod -R a-x /home/bob
      • Changing another user’s permissions, so have to do it with sudo
  • man chmod for more information.

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