👤
Home Man
Search
Today's Posts
Register

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:
Select Section of Man Page:
Select Man Page Repository:

OpenSolaris 2009.06 - man page for read (opensolaris section 1)

read(1) 				  User Commands 				  read(1)

NAME
       read - read a line from standard input

SYNOPSIS
       /usr/bin/read [-r] var...

   sh
       read name...

   csh
       set variable= $<

   ksh
       read [-prsu [n]] [name ? prompt] [name]...

   ksh93
       read [-Aprs] [-d delim] [-n nsize] [-N nsize] [-t timeout][-u unit] [vname?prompt] [vname... ]

DESCRIPTION
   /usr/bin/read
       The read utility reads a single line from standard input.

       By  default, unless the -r option is specified, backslash (\) acts as an escape character.
       If standard input is a terminal device and the invoking shell is interactive, read prompts
       for a continuation line when:

	   o	  The  shell reads an input line ending with a backslash, unless the -r option is
		  specified.

	   o	  A here-document is not terminated after a NEWLINE character is entered.

       The line is split into fields as in the shell. The first field is assigned  to  the  first
       variable  var,  the  second  field  to the second variable var, and so forth. If there are
       fewer var operands specified than there are fields, the leftover fields and  their  inter-
       vening  separators  is  assigned to the last var. If there are fewer fields than vars, the
       remaining vars is set to empty strings.

       The setting of variables specified by the var operands affects the current shell execution
       environment.  If  it  is  called in a sub-shell or separate utility execution environment,
       such as one of the following:

	 (read foo)
	 nohup read ...
	 find . -exec read ... \;

       it does not affect the shell variables in the caller's environment.

       The standard input must be a text file.

   sh
       One line is read from the standard input and, using  the  internal  field  separator,  IFS
       (normally  space  or  tab),  to delimit word boundaries, the first word is assigned to the
       first name, the second word to the second name, and so on, with leftover words assigned to
       the last name. Lines can be continued using \newline. Characters other than NEWLINE can be
       quoted by preceding them with a backslash. These backslashes are removed before words  are
       assigned  to  names, and no interpretation is done on the character that follows the back-
       slash. The return code is 0, unless an end-of-file is encountered.

   csh
       The notation:

	 set variable = $<

       loads one line of standard input as the value for variable. (See csh(1)).

   ksh
       The shell input mechanism. One line is read and is broken up into fields using the charac-
       ters  in IFS as separators. The escape character, (\), is used to remove any special mean-
       ing for the next character and for line continuation. In raw mode, the -r, the , and the \
       character  are  not  treated specially. The first field is assigned to the first name, the
       second field to the second name, and so on, with leftover  fields  assigned  to	the  last
       name.  The  -p  option  causes the input line to be taken from the input pipe of a process
       spawned by the shell using |&. If the -s flag is present, the input is saved as a  command
       in the history file. The flag -u can be used to specify a one digit file descriptor unit n
       to read from. The file descriptor can be opened with the exec special command. The default
       value of n is 0. If name is omitted, REPLY is used as the default name. The exit status is
       0 unless the input file is not open for reading or an end-of-file is encountered. An  end-
       of-file with the -p option causes cleanup for this process so that another can be spawned.
       If the first argument contains a ?, the remainder of this word is  used	as  a  prompt  on
       standard  error	when the shell is interactive. The exit status is 0 unless an end-of-file
       is encountered.

   ksh93
       read reads a line from standard input and breaks it into fields using  the  characters  in
       the  value  of  the IFS variable as separators. The escape character, \, is used to remove
       any special meaning for the next character and for line continuation unless the -r  option
       is specified.

       If there are more variables than fields, the remaining variables are set to empty strings.
       If there are fewer variables than fields, the leftover fields and their intervening  sepa-
       rators  are  assigned  to the last variable. If no var is specified, the variable REPLY is
       used.

       When var has the binary attribute and -n or -N is specified, the bytes that are	read  are
       stored directly into var.

       If  you specify ?prompt after the first var, read displays a prompt on standard error when
       standard input is a terminal or pipe.

OPTIONS
   /usr/bin/read, ksh
       The following option is supported by /usr/bin/read and ksh:

       -r    Do not treat a backslash character in any special way. Considers each  backslash  to
	     be part of the input line.

   ksh93
       The following options are supported by ksh93:

       -A	     Unset  var,  and  create  an indexed array containing each field in the line
		     starting at index 0.

       -d delim      Read until delimiter delim instead of to the end of line.

       -n nsize      Read at most nsize bytes. Binary field size is in bytes.

       -N nsize      Read exactly nsize bytes. Binary field size is in bytes.

       -p	     Read from the current co-process instead of standard input. An end  of  file
		     causes read to disconnect the co-process so that another can be created.

       -r	     Do not treat \ specially when processing the input line.

       -s	     Save a copy of the input as an entry in the shell history file.

       -t timeout    Specify a timeout in seconds when reading from a terminal or pipe.

       -u fd	     Read  from  file descriptor number fd instead of standard input. The default
		     value is 0.

       -v	     When reading from a terminal, display the value of the  first  variable  and
		     use it as a default value.

OPERANDS
       The following operand is supported:

       var    The name of an existing or non-existing shell variable.

EXAMPLES
       Example 1 Using the read Command

       The  following  example	for /usr/bin/read prints a file with the first field of each line
       moved to the end of the line:

	 example% while read -r xx yy
	 do
		 printf "%s %s\n" "$yy" "$xx"
	 done < input_file

ENVIRONMENT VARIABLES
       See environ(5) for descriptions of the following environment  variables	that  affect  the
       execution of read: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES, and NLSPATH.

       IFS    Determines the internal field separators used to delimit fields.

       PS2    Provides	the prompt string that an interactive shell writes to standard error when
	      a line ending with a backslash is read and the -r option was not specified, or if a
	      here-document is not terminated after a NEWLINE character is entered.

EXIT STATUS
       The following exit values are returned:

       0     Successful completion.

       >0    End-of-file was detected or an error occurred.

ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:

   /usr/bin/read, csh, ksh, sh
       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Committed 		   |
       +-----------------------------+-----------------------------+
       |Standard		     |See standards(5). 	   |
       +-----------------------------+-----------------------------+

   ksh93
       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Uncommitted		   |
       +-----------------------------+-----------------------------+

SEE ALSO
       csh(1), ksh(1), ksh93(1), line(1), set(1), sh(1), attributes(5), environ(5), standards(5)

SunOS 5.11				   18 Dec 2007					  read(1)


All times are GMT -4. The time now is 12:50 AM.



All times are GMT -4. The time now is 12:50 AM.

Unix & Linux Forums Content Copyrightę1993-2018. All Rights Reserved.
×
UNIX.COM Login
Username:
Password:  
Show Password