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端末から結果の特定の部分を出力するにはどうすればよいですかman something？

たとえば、C関数writeの戻り値に関する情報を取得するには、次のような内容が表示されると予想されます。

RETURN VALUE
       On  success,  the  number  of bytes written is returned (zero indicates
       nothing was written).  It is not an error if  this  number  is  smaller
       than the number of bytes requested; this may happen for example because
       the disk device was filled.  See also NOTES.

       On error, -1 is returned, and errno is set appropriately.

       If count is zero and fd refers to a  regular  file,  then  write()  may
       return  a failure status if one of the errors below is detected.  If no
       errors are detected, or error detection is not  performed,  0  will  be
       returned  without  causing  any  other effect.  If count is zero and fd
       refers to a file other than a regular file, the results are not  speci‐
       fied.

ERRORS
       EAGAIN The  file descriptor fd refers to a file other than a socket and
          has been marked nonblocking (O_NONBLOCK), and  the  write  would
          block.  See open(2) for further details on the O_NONBLOCK flag.

       EAGAIN or EWOULDBLOCK
          The  file  descriptor  fd refers to a socket and has been marked
          nonblocking   (O_NONBLOCK),   and   the   write   would   block.
[...]

変える:

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

NAME
       write - write to a file descriptor

SYNOPSIS
       #include <unistd.h>

       ssize_t write(int fd, const void *buf, size_t count);

DESCRIPTION
       write()  writes  up  to  count bytes from the buffer pointed buf to the
       file referred to by the file descriptor fd.

       The number of bytes written may be less than  count  if,  for  example,
       there  is  insufficient space on the underlying physical medium, or the
       RLIMIT_FSIZE resource limit is encountered (see setrlimit(2)),  or  the
       call was interrupted by a signal handler after having written less than
       count bytes.  (See also pipe(7).)

       For a seekable file (i.e., one to which lseek(2) may  be  applied,  for
       example,  a  regular file) writing takes place at the current file off‐
       set, and the file offset is incremented by the number of bytes actually

[...]