What does the command `chmod 755 filename` accomplish?

The command chmod 755 filename adjusts file permissions in a Linux operating system for a specified file named "filename". In this command, the number 755 represents the permission settings granted to the owner, group, and others.

Breaking this down:

• The first digit, 7, indicates that the owner of the file has read (4), write (2), and execute (1) permissions, which add up to 7.

• The second digit, 5, means that the group has read (4) and execute (1) permissions, totaling 5. This means members of the group can read the file and execute it if it's a script or binary.

• The last digit, also 5, mirrors the same permissions for others, allowing them to read and execute the file but not to modify it.

Thus, using chmod 755 grants the owner full access to the file while providing group members and others with the ability to read and execute the file but not modify its content. This is a common permission setup for scripts and applications that need to be run by others without allowing them to change the code.