FreeBSD has chflags utility or command which modifies the file flags of the listed files as specified by the flags operand. See tutorial on how to Setup file immutable bit which is just like Linux chatter command. Following are flags

• arch: set the archived flag
• nodump: set the nodump flag
• sappnd: set the system append-only flag
• schg: set the system immutable flag
• sunlnk: set the system undeletable flag
• uappnd: set the user append-only flag
• uchg: set the user immutable flag
• uunlnk: set the user undeletable flag