UNIX TUTORIALS - Unix - Quoting Mechanisms

Unix - Quoting Mechanisms

Example:

Quoting	Description
Single quote	All special characters between these quotes lose their special meaning.
Double quote	Most special characters between these quotes lose their special meaning with these exceptions: $ ` \$ \' \" \\
Backslash	Any character immediately following the backslash loses its special meaning.
Back Quote	Anything in between back quotes would be treated as a command and would be executed.

The Metacharacters:

* ? [ ] ' " \ $ ; & ( ) | ^ < > new-line space tab

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						Example:

#!/bin/sh

echo Hello; Word

						
Hello
./test.sh: line 2: Word: command not found

shell returned 127

						
#!/bin/sh

echo Hello\; Word

						
Hello; Word

						
#!/bin/sh

echo "I have \$1200"

						
I have $1200

						The Single Quotes:

echo <-$1500.**>; (update?) [y|n]

						
echo \<-\$1500.\*\*\>\; \(update\?\) \[y\|n\]

						
echo '<-$1500.**>; (update?) [y|n]'

						
echo 'It\'s Shell Programming'

						The Double Quotes:


VAR=ZARA
echo '$VAR owes <-$1500.**>; [ as of (`date +%m/%d`) ]'

						
$VAR owes <-$1500.**>; [ as of (`date +%m/%d`) ]

						
VAR=ZARA
echo "$VAR owes <-\$1500.**>; [ as of (`date +%m/%d`) ]"

						
ZARA owes <-$1500.**>; [ as of (07/02) ]

						
echo 'It\'s Shell Programming'

						Example:

var=`command`

						Example:

DATE=`date`

echo "Current Date: $DATE"

						
Current Date: Thu Jul  2 05:28:45 MST 2009