将linux的manpages换成中文并且是彩色的

一种解决方法:https://blog.csdn.net/qq_23274715/article/details/104710448

具体方法ubuntu:

1、安装软件包

  sudo apt update

  sudo apt install manpages-zh.使用此命令安装中文manpages库。

2、查看中文包的安装路径
  dpkg -L manpages-zh 使用此命令查看manpages-zh库的安装路径。如/usr/share/man/zh_CN/,几乎是默认的。

3、测试中文安装包是否有问题,以open为例
  man -M /usr/share/man/zh_CN open 其中使用此命令测试中文包是否好使(open函数的介绍为中文则表示好使)。注意,命令中的路径/usr/share/man/zh_CN为上一步查看得到的路径。
4、借助linux下的alias命令,给中文man取名为cman,方便后期使用。
  su root切换为root权限。
  echo "alias cman='man -M /usr/share/man/zh_CN'" >> /etc/profile.d/cman.sh。注意/usr/share/man/zh_CN路径的正确性。
  source /etc/profile.d/cman.sh.

5、此时cman open.命令的效果和man -M /usr/share/man/zh_CN open命令的效果一致,则设置成功。

  以上解决方案有点每种虽然可以保留英文帮助的同时,又可以使用中文帮助,但是,还是不够方便。毕竟中国人看中文更方便,因此,应该是修改英文帮助更合适。我的解决方案为:

1、安装软件包

  sudo apt update

  sudo apt install manpages-zh.使用此命令安装中文manpages库。

2、查看中文包的安装路径
  dpkg -L manpages-zh 使用此命令查看manpages-zh库的安装路径。如/usr/share/man/zh_CN/,几乎是默认的。

3、测试中文安装包是否有问题,以open为例
  man -M /usr/share/man/zh_CN open 其中使用此命令测试中文包是否好使(open函数的介绍为中文则表示好使)。注意,命令中的路径/usr/share/man/zh_CN为上一步查看得到的路径。

4、移花接木,让系统默认使用中文帮助,需要英文时,man取名为eman,方便后期使用。
  su root切换为root权限。

  sudo mkdir man_AM  建立英文帮助目录

  sudo mv man{1..8} man_AM/   将英文帮助文档放进man_AM目录

  sudo cp -R zh_CN/man{1..8} .  将中文帮助文件复制到当前目录下,系统就会默认使用中文的帮助了  

5、借助linux下的alias命令,给英文man取名为eman,方便后期使用。
  su root切换为root权限。
  echo "alias eman='man -M /usr/share/man/man_AM'" >> /etc/profile.d/eman.sh。注意/usr/share/man/man_AM路径的正确性。

  或者:sudo vim /etc/profile.d/eman.sh, 文件中填入:alias eman='man -M /usr/share/man/man_AM'  注意这里的是单引号,不是命令转接符
  source /etc/profile.d/eman.sh.

6、此时man open.命令的效果和man -M /usr/share/man/zh_CN open命令的效果一致,打开就是则设置成功。

      如果需要查看英文帮助,就用eman open

OPEN(2)                    Linux Programmer's Manual                   OPEN(2)

NAME
       open, openat, creat - open and possibly create a file

SYNOPSIS
       #include <sys/types.h>
       #include <sys/stat.h>
       #include <fcntl.h>

       int open(const char *pathname, int flags);
       int open(const char *pathname, int flags, mode_t mode);

       int creat(const char *pathname, mode_t mode);

       int openat(int dirfd, const char *pathname, int flags);
       int openat(int dirfd, const char *pathname, int flags, mode_t mode);

       /* Documented separately, in openat2(2): */
       int openat2(int dirfd, const char *pathname,
                   const struct open_how *how, size_t size);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       openat():
           Since glibc 2.10:
               _POSIX_C_SOURCE >= 200809L
           Before glibc 2.10:
               _ATFILE_SOURCE

DESCRIPTION
       The  open()  system  call opens the file specified by pathname.  If the
       specified file does not exist, it may optionally (if O_CREAT is  speci‐
       fied in flags) be created by open().

       The  return  value of open() is a file descriptor, a small, nonnegative
       integer that is used in subsequent  system  calls  (read(2),  write(2),
       lseek(2), fcntl(2), etc.) to refer to the open file.  The file descrip‐
       tor returned by a successful call will be the lowest-numbered file  de‐
       scriptor not currently open for the process.

       By default, the new file descriptor is set to remain open across an ex‐
       ecve(2) (i.e., the FD_CLOEXEC file descriptor  flag  described  in  fc‐
       ntl(2) is initially disabled); the O_CLOEXEC flag, described below, can
       be used to change this default.  The file offset is set to  the  begin‐
       ning of the file (see lseek(2)).

       A  call  to open() creates a new open file description, an entry in the
       system-wide table of open files.  The open file description records the
       file  offset  and the file status flags (see below).  A file descriptor
       is a reference to an open file description;  this  reference  is  unaf‐
       fected  if  pathname  is subsequently removed or modified to refer to a
       different file.  For further details on  open  file  descriptions,  see
       NOTES.

       The  argument  flags  must  include  one of the following access modes:
       O_RDONLY, O_WRONLY, or O_RDWR.  These request opening  the  file  read-
       only, write-only, or read/write, respectively.

       In addition, zero or more file creation flags and file status flags can
       be bitwise-or'd in flags.   The  file  creation  flags  are  O_CLOEXEC,
       O_CREAT,  O_DIRECTORY,  O_EXCL,  O_NOCTTY,  O_NOFOLLOW,  O_TMPFILE, and
       O_TRUNC.  The file status flags are all of the remaining  flags  listed
       below.   The  distinction between these two groups of flags is that the
       file creation flags affect the semantics of the open operation  itself,
       while  the file status flags affect the semantics of subsequent I/O op‐
       erations.  The file status flags can be retrieved and (in  some  cases)
       modified; see fcntl(2) for details.

       The  full  list of file creation flags and file status flags is as fol‐
       lows:

       O_APPEND
              The file is opened in append mode.  Before  each  write(2),  the
              file  offset  is  positioned  at the end of the file, as if with
              lseek(2).  The modification of the file offset and the write op‐
              eration are performed as a single atomic step.

              O_APPEND  may lead to corrupted files on NFS filesystems if more
              than one process appends data to a file at once.   This  is  be‐
              cause  NFS  does  not support appending to a file, so the client
              kernel has to simulate it, which can't be done  without  a  race
              condition.

       O_ASYNC
              Enable  signal-driven  I/O: generate a signal (SIGIO by default,
              but this can be changed via fcntl(2)) when input or  output  be‐
              comes  possible on this file descriptor.  This feature is avail‐
              able only for terminals, pseudoterminals,  sockets,  and  (since
              Linux  2.6)  pipes and FIFOs.  See fcntl(2) for further details.
              See also BUGS, below.

       O_CLOEXEC (since Linux 2.6.23)
              Enable the close-on-exec  flag  for  the  new  file  descriptor.
              Specifying  this  flag permits a program to avoid additional fc‐
              ntl(2) F_SETFD operations to set the FD_CLOEXEC flag.

              Note that the use of this  flag  is  essential  in  some  multi‐
              threaded programs, because using a separate fcntl(2) F_SETFD op‐
              eration to set the FD_CLOEXEC flag does  not  suffice  to  avoid
              race conditions where one thread opens a file descriptor and at‐
              tempts to set its close-on-exec flag using fcntl(2) at the  same
              time as another thread does a fork(2) plus execve(2).  Depending
              on the order of execution, the race may lead  to  the  file  de‐
              scriptor  returned by open() being unintentionally leaked to the
              program executed by the child process created by fork(2).  (This
              kind  of  race is in principle possible for any system call that
              creates a file descriptor whose  close-on-exec  flag  should  be
              set,  and various other Linux system calls provide an equivalent
              of the O_CLOEXEC flag to deal with this problem.)

       O_CREAT
              If pathname does not exist, create it as a regular file.

              The owner (user ID) of the new file is set to the effective user
              ID of the process.

              The  group ownership (group ID) of the new file is set either to
              the effective group ID of the process (System V semantics) or to
              the group ID of the parent directory (BSD semantics).  On Linux,
              the behavior depends on whether the set-group-ID mode bit is set
              on  the parent directory: if that bit is set, then BSD semantics
              apply; otherwise, System V semantics apply.  For  some  filesys‐
              tems,  the behavior also depends on the bsdgroups and sysvgroups
              mount options described in mount(8).

              The mode argument specifies the file mode  bits  to  be  applied
              when a new file is created.  If neither O_CREAT nor O_TMPFILE is
              specified in flags, then mode is ignored (and can thus be speci‐
              fied  as  0, or simply omitted).  The mode argument must be sup‐
              plied if O_CREAT or O_TMPFILE is specified in flags;  if  it  is
              not  supplied,  some  arbitrary bytes from the stack will be ap‐
              plied as the file mode.

              The effective mode is modified by the  process's  umask  in  the
              usual way: in the absence of a default ACL, the mode of the cre‐
              ated file is (mode & ~umask).

              Note that mode applies only to future accesses of the newly cre‐
              ated  file;  the  open()  call that creates a read-only file may
              well return a read/write file descriptor.

              The following symbolic constants are provided for mode:

              S_IRWXU  00700 user (file owner) has read,  write,  and  execute
                       permission

              S_IRUSR  00400 user has read permission

              S_IWUSR  00200 user has write permission

              S_IXUSR  00100 user has execute permission

              S_IRWXG  00070 group has read, write, and execute permission

              S_IRGRP  00040 group has read permission

              S_IWGRP  00020 group has write permission

              S_IXGRP  00010 group has execute permission

              S_IRWXO  00007 others have read, write, and execute permission

              S_IROTH  00004 others have read permission

              S_IWOTH  00002 others have write permission

              S_IXOTH  00001 others have execute permission

              According  to  POSIX, the effect when other bits are set in mode
              is unspecified.  On Linux, the following bits are  also  honored
              in mode:

              S_ISUID  0004000 set-user-ID bit

              S_ISGID  0002000 set-group-ID bit (see inode(7)).

              S_ISVTX  0001000 sticky bit (see inode(7)).

       O_DIRECT (since Linux 2.4.10)
              Try  to minimize cache effects of the I/O to and from this file.
              In general this will degrade performance, but it  is  useful  in
              special  situations,  such  as  when  applications  do their own
              caching.  File I/O is done directly to/from user-space  buffers.
              The  O_DIRECT  flag  on its own makes an effort to transfer data
              synchronously, but does not give the guarantees  of  the  O_SYNC
              flag that data and necessary metadata are transferred.  To guar‐
              antee synchronous I/O, O_SYNC must be used in addition to  O_DI‐
              RECT.  See NOTES below for further discussion.

              A  semantically similar (but deprecated) interface for block de‐
              vices is described in raw(8).

       O_DIRECTORY
              If pathname is not a directory, cause the open  to  fail.   This
              flag  was  added  in kernel version 2.1.126, to avoid denial-of-
              service problems if opendir(3) is called on a FIFO or  tape  de‐
              vice.

       O_DSYNC
              Write  operations on the file will complete according to the re‐
              quirements of synchronized I/O data integrity completion.

              By the time write(2) (and similar) return, the output  data  has
              been transferred to the underlying hardware, along with any file
              metadata that would be required to retrieve that data (i.e.,  as
              though  each  write(2)  was followed by a call to fdatasync(2)).
              See NOTES below.

       O_EXCL Ensure that this call creates the file: if this flag  is  speci‐
              fied  in  conjunction with O_CREAT, and pathname already exists,
              then open() fails with the error EEXIST.

              When these two flags are specified, symbolic links are not  fol‐
              lowed: if pathname is a symbolic link, then open() fails regard‐
              less of where the symbolic link points.

              In general, the behavior of O_EXCL is undefined if  it  is  used
              without  O_CREAT.   There  is  one  exception:  on Linux 2.6 and
              later, O_EXCL can be used without O_CREAT if pathname refers  to
              a  block  device.   If  the block device is in use by the system
              (e.g., mounted), open() fails with the error EBUSY.

              On NFS, O_EXCL is supported only when using NFSv3  or  later  on
              kernel  2.6  or later.  In NFS environments where O_EXCL support
              is not provided, programs that rely on it for performing locking
              tasks  will  contain  a  race condition.  Portable programs that
              want to perform atomic file locking using a lockfile,  and  need
              to avoid reliance on NFS support for O_EXCL, can create a unique
              file on the same filesystem (e.g.,  incorporating  hostname  and
              PID),  and  use  link(2)  to  make  a  link to the lockfile.  If
              link(2) returns 0,  the  lock  is  successful.   Otherwise,  use
              stat(2)  on  the  unique file to check if its link count has in‐
              creased to 2, in which case the lock is also successful.

       O_LARGEFILE
              (LFS) Allow files whose sizes cannot be represented in an  off_t
              (but  can  be  represented  in  an  off64_t)  to be opened.  The
              _LARGEFILE64_SOURCE macro must be defined (before including  any
              header  files)  in order to obtain this definition.  Setting the
              _FILE_OFFSET_BITS feature test macro to 64  (rather  than  using
              O_LARGEFILE) is the preferred method of accessing large files on
              32-bit systems (see feature_test_macros(7)).

       O_NOATIME (since Linux 2.6.8)
              Do not update the file last access time (st_atime in the  inode)
              when the file is read(2).

              This  flag  can  be employed only if one of the following condi‐
              tions is true:

              *  The effective UID of the process matches the owner UID of the
                 file.

              *  The calling process has the CAP_FOWNER capability in its user
                 namespace and the owner UID of the file has a mapping in  the
                 namespace.

              This  flag  is  intended for use by indexing or backup programs,
              where its use can significantly reduce the amount of disk activ‐
              ity.   This  flag  may not be effective on all filesystems.  One
              example is NFS, where the server maintains the access time.

       O_NOCTTY
              If pathname refers to a terminal device—see tty(4)—it  will  not
              become  the  process's  controlling terminal even if the process
              does not have one.

       O_NOFOLLOW
              If the trailing component (i.e., basename) of pathname is a sym‐
              bolic link, then the open fails, with the error ELOOP.  Symbolic
              links in earlier components of the pathname will still  be  fol‐
              lowed.   (Note  that the ELOOP error that can occur in this case
              is indistinguishable from the case where an open  fails  because
              there  are  too many symbolic links found while resolving compo‐
              nents in the prefix part of the pathname.)

              This flag is a FreeBSD extension, which was added  to  Linux  in
              version  2.1.126,  and  has  subsequently  been  standardized in
              POSIX.1-2008.

              See also O_PATH below.

       O_NONBLOCK or O_NDELAY
              When possible, the file is opened in nonblocking mode.   Neither
              the  open()  nor  any  subsequent I/O operations on the file de‐
              scriptor which is returned will cause  the  calling  process  to
              wait.

              Note  that  the setting of this flag has no effect on the opera‐
              tion of poll(2), select(2), epoll(7), and similar,  since  those
              interfaces  merely  inform  the  caller about whether a file de‐
              scriptor is "ready", meaning that an I/O operation performed  on
              the  file  descriptor  with  the O_NONBLOCK flag clear would not
              block.

              Note that this flag has no effect for regular  files  and  block
              devices;  that  is, I/O operations will (briefly) block when de‐
              vice activity is required, regardless of whether  O_NONBLOCK  is
              set.   Since  O_NONBLOCK  semantics  might  eventually be imple‐
              mented, applications should not depend  upon  blocking  behavior
              when specifying this flag for regular files and block devices.

              For  the handling of FIFOs (named pipes), see also fifo(7).  For
              a discussion of the effect of  O_NONBLOCK  in  conjunction  with
              mandatory file locks and with file leases, see fcntl(2).

       O_PATH (since Linux 2.6.39)
              Obtain  a  file descriptor that can be used for two purposes: to
              indicate a location in the filesystem tree and to perform opera‐
              tions  that  act  purely at the file descriptor level.  The file
              itself is not opened, and other file operations (e.g.,  read(2),
              write(2), fchmod(2), fchown(2), fgetxattr(2), ioctl(2), mmap(2))
              fail with the error EBADF.

              The following operations can be performed on the resulting  file
              descriptor:

              *  close(2).

              *  fchdir(2),  if  the  file  descriptor  refers  to a directory
                 (since Linux 3.5).

              *  fstat(2) (since Linux 3.6).

              *  fstatfs(2) (since Linux 3.12).

              *  Duplicating the file descriptor  (dup(2),  fcntl(2)  F_DUPFD,
                 etc.).

              *  Getting  and  setting file descriptor flags (fcntl(2) F_GETFD
                 and F_SETFD).

              *  Retrieving open file status flags using the fcntl(2)  F_GETFL
                 operation: the returned flags will include the bit O_PATH.

              *  Passing the file descriptor as the dirfd argument of openat()
                 and the other "*at()" system calls.  This includes  linkat(2)
                 with  AT_EMPTY_PATH  (or  via procfs using AT_SYMLINK_FOLLOW)
                 even if the file is not a directory.

              *  Passing the file descriptor to another process via a UNIX do‐
                 main socket (see SCM_RIGHTS in unix(7)).

              When  O_PATH  is  specified  in  flags,  flag  bits  other  than
              O_CLOEXEC, O_DIRECTORY, and O_NOFOLLOW are ignored.

              Opening a file or directory with the  O_PATH  flag  requires  no
              permissions  on the object itself (but does require execute per‐
              mission on the directories in the path  prefix).   Depending  on
              the  subsequent operation, a check for suitable file permissions
              may be performed (e.g., fchdir(2) requires execute permission on
              the  directory referred to by its file descriptor argument).  By
              contrast, obtaining a reference to a filesystem object by  open‐
              ing it with the O_RDONLY flag requires that the caller have read
              permission on the object, even  when  the  subsequent  operation
              (e.g.,  fchdir(2), fstat(2)) does not require read permission on
              the object.

              If pathname is a symbolic link and the O_NOFOLLOW flag  is  also
              specified,  then the call returns a file descriptor referring to
              the symbolic link.  This file descriptor  can  be  used  as  the
              dirfd  argument  in calls to fchownat(2), fstatat(2), linkat(2),
              and readlinkat(2) with an empty pathname to have the calls oper‐
              ate on the symbolic link.

              If  pathname  refers to an automount point that has not yet been
              triggered, so no other filesystem is mounted  on  it,  then  the
              call returns a file descriptor referring to the automount direc‐
              tory without triggering a mount.  fstatfs(2) can then be used to
              determine  if  it  is,  in  fact, an untriggered automount point
              (.f_type == AUTOFS_SUPER_MAGIC).

              One use of O_PATH for regular files is to provide the equivalent
              of  POSIX.1's  O_EXEC  functionality.  This permits us to open a
              file for which we have execute permission but not  read  permis‐
              sion,  and then execute that file, with steps something like the
              following:

                  char buf[PATH_MAX];
                  fd = open("some_prog", O_PATH);
                  snprintf(buf, PATH_MAX, "/proc/self/fd/%d", fd);
                  execl(buf, "some_prog", (char *) NULL);

              An O_PATH file descriptor can also be passed as the argument  of
              fexecve(3).

       O_SYNC Write  operations on the file will complete according to the re‐
              quirements of synchronized I/O  file  integrity  completion  (by
              contrast  with  the  synchronized  I/O data integrity completion
              provided by O_DSYNC.)

              By the time write(2) (or similar) returns, the output  data  and
              associated file metadata have been transferred to the underlying
              hardware (i.e., as though each write(2) was followed by  a  call
              to fsync(2)).  See NOTES below.

       O_TMPFILE (since Linux 3.11)
              Create an unnamed temporary regular file.  The pathname argument
              specifies a directory; an unnamed inode will be created in  that
              directory's  filesystem.  Anything written to the resulting file
              will be lost when the last file descriptor is closed, unless the
              file is given a name.

              O_TMPFILE  must be specified with one of O_RDWR or O_WRONLY and,
              optionally, O_EXCL.  If O_EXCL is not specified, then  linkat(2)
              can be used to link the temporary file into the filesystem, mak‐
              ing it permanent, using code like the following:

                  char path[PATH_MAX];
                  fd = open("/path/to/dir", O_TMPFILE | O_RDWR,
                                          S_IRUSR | S_IWUSR);

                  /* File I/O on 'fd'... */

                  linkat(fd, NULL, AT_FDCWD, "/path/for/file", AT_EMPTY_PATH);

                  /* If the caller doesn't have the CAP_DAC_READ_SEARCH
                     capability (needed to use AT_EMPTY_PATH with linkat(2)),
                     and there is a proc(5) filesystem mounted, then the
                     linkat(2) call above can be replaced with:

                  snprintf(path, PATH_MAX,  "/proc/self/fd/%d", fd);
                  linkat(AT_FDCWD, path, AT_FDCWD, "/path/for/file",
                                          AT_SYMLINK_FOLLOW);
                  */

              In this case, the open() mode argument determines the file  per‐
              mission mode, as with O_CREAT.

              Specifying  O_EXCL in conjunction with O_TMPFILE prevents a tem‐
              porary file from being linked into the filesystem in  the  above
              manner.   (Note  that the meaning of O_EXCL in this case is dif‐
              ferent from the meaning of O_EXCL otherwise.)

              There are two main use cases for O_TMPFILE:

              *  Improved tmpfile(3) functionality: race-free creation of tem‐
                 porary  files that (1) are automatically deleted when closed;
                 (2) can never be reached via any pathname; (3) are  not  sub‐
                 ject to symlink attacks; and (4) do not require the caller to
                 devise unique names.

              *  Creating a file that is initially invisible,  which  is  then
                 populated with data and adjusted to have appropriate filesys‐
                 tem attributes  (fchown(2),  fchmod(2),  fsetxattr(2),  etc.)
                 before being atomically linked into the filesystem in a fully
                 formed state (using linkat(2) as described above).

              O_TMPFILE requires support by the underlying filesystem; only  a
              subset  of  Linux filesystems provide that support.  In the ini‐
              tial implementation, support was provided  in  the  ext2,  ext3,
              ext4,  UDF,  Minix,  and  shmem  filesystems.  Support for other
              filesystems has subsequently been added as follows:  XFS  (Linux
              3.15);  Btrfs  (Linux 3.16); F2FS (Linux 3.16); and ubifs (Linux
              4.9)

       O_TRUNC
              If the file already exists and is a regular file and the  access
              mode  allows  writing  (i.e.,  is O_RDWR or O_WRONLY) it will be
              truncated to length 0.  If the file is a FIFO or terminal device
              file,  the  O_TRUNC  flag  is ignored.  Otherwise, the effect of
              O_TRUNC is unspecified.

   creat()
       A call to creat() is equivalent to calling open() with flags  equal  to
       O_CREAT|O_WRONLY|O_TRUNC.

   openat()
       The  openat()  system  call operates in exactly the same way as open(),
       except for the differences described here.

       If the pathname given in pathname is relative, then it  is  interpreted
       relative  to  the  directory  referred  to by the file descriptor dirfd
       (rather than relative to the current working directory of  the  calling
       process, as is done by open() for a relative pathname).

       If  pathname  is relative and dirfd is the special value AT_FDCWD, then
       pathname is interpreted relative to the current  working  directory  of
       the calling process (like open()).

       If pathname is absolute, then dirfd is ignored.

   openat2(2)
       The  openat2(2) system call is an extension of openat(), and provides a
       superset of the features of openat().  It is documented separately,  in
       openat2(2).

RETURN VALUE
       open(), openat(), and creat() return the new file descriptor (a nonneg‐
       ative integer), or -1 if an error occurred (in which case, errno is set
       appropriately).

ERRORS
       open(), openat(), and creat() can fail with the following errors:

       EACCES The  requested access to the file is not allowed, or search per‐
              mission is denied for one of the directories in the path  prefix
              of  pathname,  or the file did not exist yet and write access to
              the parent directory is not  allowed.   (See  also  path_resolu‐
              tion(7).)

       EACCES Where   O_CREAT   is  specified,  the  protected_fifos  or  pro‐
              tected_regular sysctl is enabled, the file already exists and is
              a  FIFO  or  regular  file, the owner of the file is neither the
              current user nor the owner of the containing directory, and  the
              containing  directory  is  both  world-  or  group-writable  and
              sticky.  For details, see the descriptions of  /proc/sys/fs/pro‐
              tected_fifos and /proc/sys/fs/protected_regular in proc(5).

       EBUSY  O_EXCL was specified in flags and pathname refers to a block de‐
              vice that is in use by the system (e.g., it is mounted).

       EDQUOT Where O_CREAT is specified, the file does  not  exist,  and  the
              user's quota of disk blocks or inodes on the filesystem has been
              exhausted.

       EEXIST pathname already exists and O_CREAT and O_EXCL were used.

       EFAULT pathname points outside your accessible address space.

       EFBIG  See EOVERFLOW.

       EINTR  While blocked waiting to complete  an  open  of  a  slow  device
              (e.g.,  a FIFO; see fifo(7)), the call was interrupted by a sig‐
              nal handler; see signal(7).

       EINVAL The filesystem does not support the O_DIRECT  flag.   See  NOTES
              for more information.

       EINVAL Invalid value in flags.

       EINVAL O_TMPFILE  was  specified  in  flags,  but  neither O_WRONLY nor
              O_RDWR was specified.

       EINVAL O_CREAT was specified in flags and the final  component  ("base‐
              name")  of the new file's pathname is invalid (e.g., it contains
              characters not permitted by the underlying filesystem).

       EINVAL The final component ("basename") of pathname is  invalid  (e.g.,
              it  contains characters not permitted by the underlying filesys‐
              tem).

       EISDIR pathname refers to a directory and the access requested involved
              writing (that is, O_WRONLY or O_RDWR is set).

       EISDIR pathname  refers  to an existing directory, O_TMPFILE and one of
              O_WRONLY or O_RDWR were specified in flags, but this kernel ver‐
              sion does not provide the O_TMPFILE functionality.

       ELOOP  Too many symbolic links were encountered in resolving pathname.

       ELOOP  pathname was a symbolic link, and flags specified O_NOFOLLOW but
              not O_PATH.

       EMFILE The per-process limit on the number of open file descriptors has
              been  reached  (see  the  description  of RLIMIT_NOFILE in getr‐
              limit(2)).

       ENAMETOOLONG
              pathname was too long.

       ENFILE The system-wide limit on the total number of open files has been
              reached.

       ENODEV pathname  refers  to  a device special file and no corresponding
              device exists.  (This is a Linux kernel bug; in  this  situation
              ENXIO must be returned.)

       ENOENT O_CREAT is not set and the named file does not exist.

       ENOENT A  directory  component  in pathname does not exist or is a dan‐
              gling symbolic link.

       ENOENT pathname refers to a nonexistent directory, O_TMPFILE and one of
              O_WRONLY or O_RDWR were specified in flags, but this kernel ver‐
              sion does not provide the O_TMPFILE functionality.

       ENOMEM The named file is a FIFO, but memory for the FIFO  buffer  can't
              be  allocated  because the per-user hard limit on memory alloca‐
              tion for pipes has been reached and the  caller  is  not  privi‐
              leged; see pipe(7).

       ENOMEM Insufficient kernel memory was available.

       ENOSPC pathname  was  to  be created but the device containing pathname
              has no room for the new file.

       ENOTDIR
              A component used as a directory in pathname is not, in  fact,  a
              directory,  or  O_DIRECTORY was specified and pathname was not a
              directory.

       ENXIO  O_NONBLOCK | O_WRONLY is set, the named file is a FIFO,  and  no
              process has the FIFO open for reading.

       ENXIO  The  file  is  a device special file and no corresponding device
              exists.

       ENXIO  The file is a UNIX domain socket.

       EOPNOTSUPP
              The filesystem containing pathname does not support O_TMPFILE.

       EOVERFLOW
              pathname refers to a regular  file  that  is  too  large  to  be
              opened.  The usual scenario here is that an application compiled
              on a 32-bit platform  without  -D_FILE_OFFSET_BITS=64  tried  to
              open  a  file  whose  size  exceeds  (1<<31)-1  bytes;  see also
              O_LARGEFILE above.  This is the error specified by  POSIX.1;  in
              kernels before 2.6.24, Linux gave the error EFBIG for this case.

       EPERM  The  O_NOATIME  flag was specified, but the effective user ID of
              the caller did not match the owner of the file  and  the  caller
              was not privileged.

       EPERM  The operation was prevented by a file seal; see fcntl(2).

       EROFS  pathname  refers  to  a file on a read-only filesystem and write
              access was requested.

       ETXTBSY
              pathname refers to an executable image which is currently  being
              executed and write access was requested.

       ETXTBSY
              pathname  refers  to  a  file that is currently in use as a swap
              file, and the O_TRUNC flag was specified.

       ETXTBSY
              pathname refers to a file that is currently being  read  by  the
              kernel (e.g., for module/firmware loading), and write access was
              requested.

       EWOULDBLOCK
              The O_NONBLOCK flag was specified, and an incompatible lease was
              held on the file (see fcntl(2)).

       The following additional errors can occur for openat():

       EBADF  dirfd is not a valid file descriptor.

       ENOTDIR
              pathname  is  a relative pathname and dirfd is a file descriptor
              referring to a file other than a directory.

VERSIONS
       openat() was added to Linux in kernel 2.6.16; library support was added
       to glibc in version 2.4.

CONFORMING TO
       open(), creat() SVr4, 4.3BSD, POSIX.1-2001, POSIX.1-2008.

       openat(): POSIX.1-2008.

       openat2(2) is Linux-specific.

       The  O_DIRECT,  O_NOATIME,  O_PATH,  and O_TMPFILE flags are Linux-spe‐
       cific.  One must define _GNU_SOURCE to obtain their definitions.

       The O_CLOEXEC, O_DIRECTORY, and O_NOFOLLOW flags are not  specified  in
       POSIX.1-2001, but are specified in POSIX.1-2008.  Since glibc 2.12, one
       can obtain their definitions by defining either _POSIX_C_SOURCE with  a
       value  greater  than  or equal to 200809L or _XOPEN_SOURCE with a value
       greater than or equal to 700.  In glibc 2.11 and earlier,  one  obtains
       the definitions by defining _GNU_SOURCE.

       As  noted  in  feature_test_macros(7),  feature  test  macros  such  as
       _POSIX_C_SOURCE, _XOPEN_SOURCE, and _GNU_SOURCE must be defined  before
       including any header files.

NOTES
       Under  Linux,  the O_NONBLOCK flag is sometimes used in cases where one
       wants to open but does not necessarily have the intention  to  read  or
       write.   For example, this may be used to open a device in order to get
       a file descriptor for use with ioctl(2).

       The (undefined) effect of O_RDONLY | O_TRUNC varies  among  implementa‐
       tions.  On many systems the file is actually truncated.

       Note that open() can open device special files, but creat() cannot cre‐
       ate them; use mknod(2) instead.

       If the file is newly created, its st_atime, st_ctime,  st_mtime  fields
       (respectively,  time  of  last  access, time of last status change, and
       time of last modification; see stat(2)) are set to  the  current  time,
       and  so  are  the st_ctime and st_mtime fields of the parent directory.
       Otherwise, if the file is modified because of  the  O_TRUNC  flag,  its
       st_ctime and st_mtime fields are set to the current time.

       The  files  in the /proc/[pid]/fd directory show the open file descrip‐
       tors of the process with the PID pid.  The files in the /proc/[pid]/fd‐
       info directory show even more information about these file descriptors.
       See proc(5) for further details of both of these directories.

       The Linux header file <asm/fcntl.h> doesn't define O_ASYNC;  the  (BSD-
       derived) FASYNC synonym is defined instead.

   Open file descriptions
       The term open file description is the one used by POSIX to refer to the
       entries in the system-wide table of open  files.   In  other  contexts,
       this  object  is  variously  also called an "open file object", a "file
       handle", an "open file table entry", or—in kernel-developer  parlance—a
       struct file.

       When a file descriptor is duplicated (using dup(2) or similar), the du‐
       plicate refers to the same open file description as the  original  file
       descriptor,  and  the  two file descriptors consequently share the file
       offset and file status flags.  Such sharing can also occur between pro‐
       cesses:  a child process created via fork(2) inherits duplicates of its
       parent's file descriptors, and those duplicates refer to the same  open
       file descriptions.

       Each  open() of a file creates a new open file description; thus, there
       may be multiple open file descriptions corresponding to a file inode.

       On Linux, one can use the kcmp(2) KCMP_FILE operation to  test  whether
       two  file  descriptors  (in  the  same process or in two different pro‐
       cesses) refer to the same open file description.

   Synchronized I/O
       The POSIX.1-2008 "synchronized I/O" option specifies different variants
       of  synchronized  I/O,  and specifies the open() flags O_SYNC, O_DSYNC,
       and O_RSYNC for controlling the behavior.  Regardless of whether an im‐
       plementation  supports this option, it must at least support the use of
       O_SYNC for regular files.

       Linux implements O_SYNC and O_DSYNC, but not O_RSYNC.  Somewhat  incor‐
       rectly,  glibc  defines  O_RSYNC  to  have  the  same  value as O_SYNC.
       (O_RSYNC is defined in the Linux header file <asm/fcntl.h>  on  HP  PA-
       RISC, but it is not used.)

       O_SYNC  provides  synchronized  I/O  file integrity completion, meaning
       write operations will flush data and all associated metadata to the un‐
       derlying  hardware.   O_DSYNC  provides synchronized I/O data integrity
       completion, meaning write operations will flush data to the  underlying
       hardware, but will only flush metadata updates that are required to al‐
       low a subsequent read operation to complete successfully.  Data  integ‐
       rity  completion  can reduce the number of disk operations that are re‐
       quired for applications that don't need the guarantees of  file  integ‐
       rity completion.

       To  understand the difference between the two types of completion, con‐
       sider two pieces of file metadata: the file last modification timestamp
       (st_mtime)  and  the file length.  All write operations will update the
       last file modification timestamp, but only writes that add data to  the
       end  of  the  file  will change the file length.  The last modification
       timestamp is not needed to ensure that a read  completes  successfully,
       but  the  file  length is.  Thus, O_DSYNC would only guarantee to flush
       updates to the file length metadata (whereas O_SYNC would  also  always
       flush the last modification timestamp metadata).

       Before Linux 2.6.33, Linux implemented only the O_SYNC flag for open().
       However, when that flag was specified, most filesystems  actually  pro‐
       vided  the  equivalent  of  synchronized  I/O data integrity completion
       (i.e., O_SYNC was actually implemented as the equivalent of O_DSYNC).

       Since Linux 2.6.33, proper O_SYNC support is provided.  However, to en‐
       sure  backward  binary compatibility, O_DSYNC was defined with the same
       value as the historical O_SYNC, and O_SYNC was defined as a  new  (two-
       bit)  flag  value  that  includes the O_DSYNC flag value.  This ensures
       that applications compiled against new headers get at least O_DSYNC se‐
       mantics on pre-2.6.33 kernels.

   C library/kernel differences
       Since  version  2.26, the glibc wrapper function for open() employs the
       openat() system call, rather than the kernel's open() system call.  For
       certain architectures, this is also true in glibc versions before 2.26.

   NFS
       There  are  many infelicities in the protocol underlying NFS, affecting
       amongst others O_SYNC and O_NDELAY.

       On NFS filesystems with UID mapping enabled, open() may return  a  file
       descriptor  but,  for example, read(2) requests are denied with EACCES.
       This is because the client performs open() by checking the permissions,
       but  UID  mapping  is  performed  by the server upon read and write re‐
       quests.

   FIFOs
       Opening the read or write end of a FIFO blocks until the other  end  is
       also  opened  (by  another process or thread).  See fifo(7) for further
       details.

   File access mode
       Unlike the other values that can be specified in flags, the access mode
       values  O_RDONLY,  O_WRONLY, and O_RDWR do not specify individual bits.
       Rather, they define the low order two bits of flags,  and  are  defined
       respectively  as 0, 1, and 2.  In other words, the combination O_RDONLY
       | O_WRONLY is a logical error, and certainly does  not  have  the  same
       meaning as O_RDWR.

       Linux  reserves  the  special, nonstandard access mode 3 (binary 11) in
       flags to mean: check for read and write permission on the file and  re‐
       turn a file descriptor that can't be used for reading or writing.  This
       nonstandard access mode is used by some Linux drivers to return a  file
       descriptor  that is to be used only for device-specific ioctl(2) opera‐
       tions.

   Rationale for openat() and other directory file descriptor APIs
       openat() and the other system calls and library functions that  take  a
       directory  file  descriptor  argument (i.e., execveat(2), faccessat(2),
       fanotify_mark(2), fchmodat(2), fchownat(2), fspick(2), fstatat(2),  fu‐
       timesat(2),    linkat(2),    mkdirat(2),   move_mount(2),   mknodat(2),
       name_to_handle_at(2),  open_tree(2),  openat2(2),  readlinkat(2),   re‐
       nameat(2),  statx(2),  symlinkat(2),  unlinkat(2),  utimensat(2), mkfi‐
       foat(3), and scandirat(3)) address two problems with the  older  inter‐
       faces  that  preceded  them.   Here, the explanation is in terms of the
       openat() call, but the rationale is analogous for the other interfaces.

       First, openat() allows an application to  avoid  race  conditions  that
       could  occur  when using open() to open files in directories other than
       the current working directory.  These race conditions result  from  the
       fact  that some component of the directory prefix given to open() could
       be changed in parallel with the call to open().  Suppose, for  example,
       that  we  wish  to  create  the  file  dir1/dir2/xxx.dep  if  the  file
       dir1/dir2/xxx exists.  The problem is that between the existence  check
       and  the  file-creation  step,  dir1  or  dir2 (which might be symbolic
       links) could be modified to point to a different location.  Such  races
       can  be  avoided by opening a file descriptor for the target directory,
       and then specifying that file descriptor as the dirfd argument of (say)
       fstatat(2) and openat().  The use of the dirfd file descriptor also has
       other benefits:

       *  the file descriptor is a stable reference to the directory, even  if
          the directory is renamed; and

       *  the open file descriptor prevents the underlying filesystem from be‐
          ing dismounted, just as when a process has a current working  direc‐
          tory on a filesystem.

       Second,  openat()  allows  the  implementation of a per-thread "current
       working directory", via file descriptor(s) maintained by  the  applica‐
       tion.   (This functionality can also be obtained by tricks based on the
       use of /proc/self/fd/dirfd, but less efficiently.)

       The dirfd argument for these APIs can be obtained by  using  open()  or
       openat()  to  open  a directory (with either the O_RDONLY or the O_PATH
       flag).  Alternatively, such a file descriptor can be obtained by apply‐
       ing dirfd(3) to a directory stream created using opendir(3).

       When these APIs are given a dirfd argument of AT_FDCWD or the specified
       pathname is absolute, then they handle their pathname argument  in  the
       same  way  as  the  corresponding  conventional APIs.  However, in this
       case, several of the APIs have a flags argument that provides access to
       functionality that is not available with the corresponding conventional
       APIs.

   O_DIRECT
       The O_DIRECT flag may impose alignment restrictions on the  length  and
       address  of  user-space  buffers and the file offset of I/Os.  In Linux
       alignment restrictions vary by filesystem and kernel version and  might
       be  absent entirely.  However there is currently no filesystem-indepen‐
       dent interface for an application to discover these restrictions for  a
       given  file  or  filesystem.  Some filesystems provide their own inter‐
       faces for doing so, for example the XFS_IOC_DIOINFO  operation  in  xf‐
       sctl(3).

       Under  Linux  2.4, transfer sizes, and the alignment of the user buffer
       and the file offset must all be multiples of the logical block size  of
       the filesystem.  Since Linux 2.6.0, alignment to the logical block size
       of the underlying storage (typically 512 bytes) suffices.  The  logical
       block  size can be determined using the ioctl(2) BLKSSZGET operation or
       from the shell using the command:

           blockdev --getss

       O_DIRECT I/Os should never be run concurrently with the fork(2)  system
       call, if the memory buffer is a private mapping (i.e., any mapping cre‐
       ated with the mmap(2) MAP_PRIVATE flag; this includes memory  allocated
       on  the heap and statically allocated buffers).  Any such I/Os, whether
       submitted via an asynchronous I/O interface or from another  thread  in
       the  process, should be completed before fork(2) is called.  Failure to
       do so can result in data corruption and undefined  behavior  in  parent
       and  child  processes.  This restriction does not apply when the memory
       buffer for the O_DIRECT I/Os was created using shmat(2) or mmap(2) with
       the  MAP_SHARED  flag.  Nor does this restriction apply when the memory
       buffer has been advised as MADV_DONTFORK with madvise(2), ensuring that
       it will not be available to the child after fork(2).

       The  O_DIRECT  flag  was introduced in SGI IRIX, where it has alignment
       restrictions similar to those of Linux 2.4.  IRIX has also  a  fcntl(2)
       call  to  query  appropriate alignments, and sizes.  FreeBSD 4.x intro‐
       duced a flag of the same name, but without alignment restrictions.

       O_DIRECT support was added under Linux in kernel version 2.4.10.  Older
       Linux kernels simply ignore this flag.  Some filesystems may not imple‐
       ment the flag, in which case open() fails with the error EINVAL  if  it
       is used.

       Applications  should  avoid  mixing O_DIRECT and normal I/O to the same
       file, and especially to overlapping byte  regions  in  the  same  file.
       Even when the filesystem correctly handles the coherency issues in this
       situation, overall I/O throughput is likely to be slower than using ei‐
       ther mode alone.  Likewise, applications should avoid mixing mmap(2) of
       files with direct I/O to the same files.

       The behavior of O_DIRECT with NFS will differ from  local  filesystems.
       Older  kernels,  or kernels configured in certain ways, may not support
       this combination.  The NFS protocol does not support passing  the  flag
       to  the  server, so O_DIRECT I/O will bypass the page cache only on the
       client; the server may still cache the I/O.  The client asks the server
       to  make  the  I/O synchronous to preserve the synchronous semantics of
       O_DIRECT.  Some servers will perform poorly under these  circumstances,
       especially  if the I/O size is small.  Some servers may also be config‐
       ured to lie to clients about the I/O  having  reached  stable  storage;
       this  will avoid the performance penalty at some risk to data integrity
       in the event of server power failure.  The Linux NFS client  places  no
       alignment restrictions on O_DIRECT I/O.

       In summary, O_DIRECT is a potentially powerful tool that should be used
       with caution.  It is recommended that applications treat use  of  O_DI‐
       RECT as a performance option which is disabled by default.

BUGS
       Currently, it is not possible to enable signal-driven I/O by specifying
       O_ASYNC when calling open(); use fcntl(2) to enable this flag.

       One must check for two different error codes, EISDIR and  ENOENT,  when
       trying  to  determine whether the kernel supports O_TMPFILE functional‐
       ity.

       When both O_CREAT and O_DIRECTORY are specified in flags and  the  file
       specified by pathname does not exist, open() will create a regular file
       (i.e., O_DIRECTORY is ignored).

SEE ALSO
       chmod(2), chown(2),  close(2),  dup(2),  fcntl(2),  link(2),  lseek(2),
       mknod(2), mmap(2), mount(2), open_by_handle_at(2), openat2(2), read(2),
       socket(2), stat(2), umask(2), unlink(2),  write(2),  fopen(3),  acl(5),
       fifo(7), inode(7), path_resolution(7), symlink(7)

COLOPHON
       This  page  is  part of release 5.10 of the Linux man-pages project.  A
       description of the project, information about reporting bugs,  and  the
       latest     version     of     this    page,    can    be    found    at
       https://www.kernel.org/doc/man-pages/.

Linux                             2020-11-01                           OPEN(2)

 

7、最后,让manpage显示的更多彩,在.bashrc文件中,添加配置文件离开;

.bashrc文件中加入如下内容:
export LESS_TERMCAP_mb=$'\E[01;31m'
export LESS_TERMCAP_md=$'\E[01;31m'
export LESS_TERMCAP_me=$'\E[0m'
export LESS_TERMCAP_se=$'\E[0m'
export LESS_TERMCAP_so=$'\E[01;44;33m'
export LESS_TERMCAP_ue=$'\E[0m'
export LESS_TERMCAP_us=$'\E[01;32m'

source .bashrc 直接生效

重启启动终端即可。

可以直接:man termcap查看帮助文件:其中常用的主要是上边列写的那几个,具体含义:

mb start blink
md start bold
me turn off bold, blink and underline
us start underline
ue stop underline
so start standout
se stop standout

 

'\E[01;44;33m'中:用;将其分为3组,第一组主要表示是否加粗,第二组主要是前景色,第三组主要是背景色;

x代表是否加粗,1为加粗,0为正常;4433分别代表文字前景色和背景色,

$后是具体你想要的颜色,具体:

经常用数字 1  2  3  4  5  6  7来代替

 以下是termcap设置less的定义:
  • LESS_TERMCAP_md: Start bold effect (double-bright).

    LESS_TERMCAP_md :开始加粗效果(双亮)。

  • LESS_TERMCAP_me: Stop bold effect.

    LESS_TERMCAP_me :停止粗体效果。

  • LESS_TERMCAP_us: Start underline effect.

    LESS_TERMCAP_us :开始下划线效果。

  • LESS_TERMCAP_ue: Stop underline effect.

    LESS_TERMCAP_ue :停止下划线效果。

  • LESS_TERMCAP_so: Start stand-out effect (similar to reverse text).

    LESS_TERMCAP_so :开始突出效果(类似于反向文本)。

  • LESS_TERMCAP_se: Stop stand-out effect (similar to reverse text).

    LESS_TERMCAP_se :停止突出效果(类似于反向文本)。

加了高亮后的manpage文件:

  有中文,也有彩色了。

 
 

 

export LESS_TERMCAP_mb=$'\E[01;31m'
export LESS_TERMCAP_md=$'\E[01;31m'
export LESS_TERMCAP_me=$'\E[0m'
export LESS_TERMCAP_se=$'\E[0m'
export LESS_TERMCAP_so=$'\E[01;44;33m'
export LESS_TERMCAP_ue=$'\E[0m'
export LESS_TERMCAP_us=$'\E[01;32m'
posted @ 2023-12-31 22:07  叕叒双又  阅读(197)  评论(1编辑  收藏  举报