🚀 go-pugleaf

On Sat, 20 Apr 2002, Puck wrote:

> > > > Pod DOS-em też to jest, tylko w prostszej implementacji.
> > > Mhm, nadal wszystko rozumiem :>
> > Używałeś kiedyś znaczków '>', '<' i '|'?
> W dosie? No zdaję sobię sprawe, co robią.

No to wyobraź sobie, że pod Linuksem to samo, tylko o wiele bardziej
zaawansowanie (np. rura może obsługiwać kilka komend jednocześnie tak,
że jedna czeka na reakcję drugiej). Dokładniejszy opis.

   Pipelines
       A pipeline is a sequence of one or more commands separated
       by the character |.  The format for a pipeline is:

              [ ! ] command [ | command2 ... ]

       The  standard  output of command is connected to the stan­
       dard input of  command2.   This  connection  is  performed
       before  any  redirections  specified  by  the command (see
       REDIRECTION below).

       If the reserved word !  precedes a pipeline, the exit sta­
       tus of that pipeline is the logical NOT of the exit status
       of  the  last  command.   Otherwise,  the  status  of  the
       pipeline  is  the  exit  status  of the last command.  The
       shell waits for all commands in the pipeline to  terminate
       before returning a value.

       Each  command in a pipeline is executed as a separate pro­
       cess (i.e., in a subshell).

REDIRECTION
       Before a command is executed, its input and output may  be
       redirected  using  a  special  notation interpreted by the
       shell.  Redirection may also be used  to  open  and  close
       files  for  the  current shell execution environment.  The
       following redirection operators may precede or appear any­
       where  within  a  simple  command or may follow a command.
       Redirections are processed in the order they appear,  from
       left to right.

       In the following descriptions, if the file descriptor num­
       ber is omitted, and the first character of the redirection
       operator  is  <,  the  redirection  refers to the standard
       input (file descriptor 0).  If the first character of  the
       redirection  operator  is >, the redirection refers to the
       standard output (file descriptor 1).

       The word that follows the redirection operator in the fol­
       lowing descriptions is subjected to brace expansion, tilde
       expansion,  parameter  expansion,  command   substitution,
       arithmetic  expansion,  quote removal, and pathname expan­
       sion.  If it expands to more than one word,  bash  reports
       an error.

       Note  that  the order of redirections is significant.  For
       example, the command

              ls > dirlist 2>&1

       directs both standard output and  standard  error  to  the
       file dirlist, while the command

              ls 2>&1 > dirlist

       directs  only the standard output to file dirlist, because
       the standard  error  was  duplicated  as  standard  output
       before the standard output was redirected to dirlist.

   Redirecting Input
       Redirection  of  input  causes the file whose name results
       from the expansion of word to be  opened  for  reading  on
       file  descriptor n, or the standard input (file descriptor
       0) if n is not specified.

       The general format for redirecting input is:

              [n]<word

   Redirecting Output
       Redirection of output causes the file whose  name  results
       from  the  expansion  of  word to be opened for writing on
       file descriptor n, or the standard output (file descriptor
       1)  if  n is not specified.  If the file does not exist it
       is created; if it does exist it is truncated to zero size.

       The general format for redirecting output is:

              [n]>word

       If  the  redirection operator is >|, then the value of the
       -C option to the set builtin command is  not  tested,  and
       file  creation is attempted.  (See also the description of
       noclobber under Shell Variables above.)

   Appending Redirected Output
       Redirection of output in  this  fashion  causes  the  file
       whose name results from the expansion of word to be opened
       for appending on file descriptor n, or the standard output
       (file  descriptor  1)  if n is not specified.  If the file
       does not exist it is created.

       The general format for appending output is:

              [n]>>word

   Redirecting Standard Output and Standard Error
       Bash allows both the standard output (file  descriptor  1)
       and  the  standard  error output (file descriptor 2) to be
       redirected to the file whose name is the expansion of word
       with this construct.

       There  are two formats for redirecting standard output and
       standard error:

              &>word
       and
              >&word

       Of the two forms, the first is preferred.  This is  seman­
       tically equivalent to

              >word 2>&1

   Here Documents
       This type of redirection instructs the shell to read input
       from the current source until a line containing only  word
       (with  no trailing blanks) is seen.  All of the lines read
       up to that point are then used as the standard input for a
       command.

       The format of here-documents is as follows:

              <<[-]word
                      here-document
              delimiter

       No  parameter  expansion,  command  substitution, pathname
       expansion, or arithmetic expansion is performed  on  word.
       If any characters in word are quoted, the delimiter is the
       result of quote removal on word,  and  the  lines  in  the
       here-document  are  not expanded.  Otherwise, all lines of
       the here-document are subjected  to  parameter  expansion,
       command  substitution,  and  arithmetic expansion.  In the
       latter case, the pair \<newline> is ignored, and \ must be
       used to quote the characters \, $, and `.

       If  the  redirection operator is <<-, then all leading tab
       characters are stripped from input lines and the line con­
       taining  delimiter.   This  allows  here-documents  within
       shell scripts to be indented in a natural fashion.

   Duplicating File Descriptors
       The redirection operator

              [n]<&word

       is used to duplicate  input  file  descriptors.   If  word
       expands to one or more digits, the file descriptor denoted
       by n is made to be a copy of  that  file  descriptor.   If
       word evaluates to -, file descriptor n is closed.  If n is
       not specified, the standard input (file descriptor  0)  is
       used.

       The operator

              [n]>&word

       is  used  similarly  to duplicate output file descriptors.
       If n is not specified, the standard output (file  descrip­
       tor  1)  is used.  As a special case, if n is omitted, and
       word does not expand to one or more digits,  the  standard
       output and standard error are redirected as described pre­
       viously.

   Opening File Descriptors for Reading and Writing
       The redirection operator

              [n]<>word

       causes the file whose name is the expansion of word to  be
       opened  for both reading and writing on file descriptor n,
       or as the standard input and standard output if n  is  not
       specified.  If the file does not exist, it is created.

> > > > DOS zamiast "Broken pipe" wyświetlał coś w stylu "Intermediate
> > > > command error during pipe" czy coś takiego, nie pamiętam.
> > > Dos wyświetlał: '...dysk nie jest już być prawidłowy...' ;)
> > A to swoją drogą. :> OE wstawia: "Użytkownik
> > (...) w wiadomości napisał:msgid...". :D
> Tak, ten colon jest co najmniej głupi.

Chodziło o to, że w oryginale jest wrote news:mid. :D

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