Heredoc

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PHP

<?php
 
$name       = "Joe Smith";
$occupation = "Programmer";
echo <<<EOF
 
This is a heredoc section.
For more information talk to $name, your local $occupation.
 
Thanks!
 
EOF;
 
$toprint = <<<EOF
 
Hey $name! You can actually assign the heredoc section to a variable!
 
EOF;
echo strtolower($toprint);
 
?>

Shell

$ cat << EOF
> Working dir $PWD
> EOF
Working dir /home/user

En un script de bash:

cat <<EOT >fitxer
From: $from
To: $to  

This is the first line of text.
This is the second line of text.
EOT

El text es guarda al fitxer fitxer.

També es pot utilitzar l'operador:

<<-

El que permet es no haver de posar les línies del heredoc totes a l'inici de la línia. Es poden utilitzar tabulador i aquest són eliminats a la sortida.

Al manual de bash:

$ man bash
...
 Here Documents
      This type of redirection instructs the shell to read input from the current source until a line containing only delimiter (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:

             <<[-]word
                     here-document
             delimiter

      No  parameter expansion, command substitution, arithmetic expansion, or pathname 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.  If word is unquoted, 
      all lines of the here-document  are  subjected  to parameter  expansion,  command substitution, and arithmetic expansion.  In the latter case, 
      the character sequence \<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  containing  delimiter.   This  
      allows  here-documents within shell scripts to be indented in a natural fashion.

• http://articles.techrepublic.com.com/5100-10878_11-5733460.html

Paraules de pas

#!/bin/bash
echo -n "Enter the Host: "
read HOST
echo -n "Enter Username: "
read USER
echo -n "Enter Password: "
read -s PASS
VAR=$(expect -c "
spawn ssh [email protected]$HOST
expect \"password:\"
send \"$PASS\r\"
expect \">\"
send \"ls\r\"
send \"echo 'I\'m on $HOST'\r\"
expect -re \"stuff\"
send \"logout\"
")
echo -e "\n\n\n========"
echo VAR = "$VAR"
echo done

Enllaços externs

• http://en.wikipedia.org/wiki/Here_document