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...]

DESCRIPTION

  /usr/bin/read
     The read utility will  read  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  will
     prompt 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 will be split into fields  as  in  the  shell.  The
     first  field will be 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 intervening separators
     will  be assigned to the last var. If there are fewer fields
     than vars, the remaining vars will be set to empty strings.

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

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

     it will 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  backslash.  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 characters in IFS as separators. The
     escape character, (\), is used to remove any special meaning
     for  the  next  character  and for line continuation. In raw
     mode, -r, the \ character  is  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 will be 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 com-
     mand. 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.

OPTIONS

     The following option is supported:

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

OPERANDS

     The following operand is supported:

     var   The name of an existing or  non-existing  shell  vari-
           able.

EXAMPLES

     Example 1: An example of 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  del-
           imit fields.

     PS2   Provides the prompt string that an  interactive  shell
           will write 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 new-
           line 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  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWcsu                     |
    |_____________________________|_____________________________|
    | Interface Stability         | Standard                    |
    |_____________________________|_____________________________|

SEE ALSO

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