gid(2) - phpMan

getegid (2)          - get group identity
getegid (3p)         - get the effective group ID
getegid32 (2)        - get group identity
getgid (2)           - get group identity
getgid (3p)          - get the real group ID
getgid32 (2)         - get group identity
getgrgid (3)         - get group file entry
getgrgid (3p)        - get group database entry for a group ID
getgrgid_r (3)       - get group file entry
getgrgid_r (3p)      - get group database entry for a group ID
getpgid (2)          - set/get process group
getpgid (3p)         - get the process group ID for a process
getresgid (2)        - get real, effective and saved user/group IDs
getresgid32 (2)      - get real, effective and saved user/group IDs
newgidmap (1)        - set the gid mapping of a user namespace
setegid (2)          - set effective user or group ID
setegid (3p)         - set the effective group ID
setfsgid (2)         - set group identity used for file system checks
setfsgid32 (2)       - set group identity used for file system checks
setgid (2)           - set group identity
setgid (3p)          - set-group-ID
setgid32 (2)         - set group identity
setpgid (2)          - set/get process group
setpgid (3p)         - set process group ID for job control
setregid (2)         - set real and/or effective user or group ID
setregid (3p)        - set real and effective group IDs
setregid32 (2)       - set real and/or effective user or group ID
setresgid (2)        - set real, effective and saved user or group ID
setresgid32 (2)      - set real, effective and saved user or group ID
subgid (5)           - the subordinate gid file