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Full Discussion: echo with a here-document
Top Forums Shell Programming and Scripting echo with a here-document Post 81409 by Unbeliever on Friday 19th of August 2005 09:48:51 AM
Old 08-19-2005
I assume its because echo (unlike most unix commands) does not 'by default' read from the stdin descriptor. All these commands simply echo a new line:

a) echo "mystring" | echo
b) cat myfile | ehho
c) echo < myfile
d) echo <<EOF
blah1
blah2
EOF

So in your second example:
Quote:
Originally Posted by vino
echo <<EOF >> /tmp/log
A Line in the log file.
The next line in the log file.
And the last line in the log file.
EOF
you are in effect doing:

echo < myinfile > myoutfile

it's just the shell is creating the file for you.
 
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escape(1)							Mail Avenger 0.8.3							 escape(1)

NAME
escape - escape shell special characters in a string SYNOPSIS
escape string DESCRIPTION
escape prepends a "" character to all shell special characters in string, making it safe to compose a shell command with the result. EXAMPLES
The following is a contrived example showing how one can unintentionally end up executing the contents of a string: $ var='; echo gotcha!' $ eval echo hi $var hi gotcha! $ Using escape, one can avoid executing the contents of $var: $ eval echo hi `escape "$var"` hi ; echo gotcha! $ A less contrived example is passing arguments to Mail Avenger bodytest commands containing possibly unsafe environment variables. For example, you might write a hypothetical reject_bcc script to reject mail not explicitly addressed to the recipient: #!/bin/sh formail -x to -x cc -x resent-to -x resent-cc | fgrep "$1" > /dev/null && exit 0 echo "<$1>.. address does not accept blind carbon copies" exit 100 To invoke this script, passing it the recipient address as an argument, you would need to put the following in your Mail Avenger rcpt script: bodytest reject_bcc `escape "$RECIPIENT"` SEE ALSO
avenger(1), The Mail Avenger home page: <http://www.mailavenger.org/>. BUGS
escape is designed for the Bourne shell, which is what Mail Avenger scripts use. escape might or might not work with other shells. AUTHOR
David Mazieres Mail Avenger 0.8.3 2012-04-05 escape(1)

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