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Full Discussion: Unix Shell Scripting
Top Forums UNIX for Dummies Questions & Answers Unix Shell Scripting Post 302686489 by Don Cragun on Tuesday 14th of August 2012 04:57:21 PM
Old 08-14-2012
First, there are two flavors of the echo utility. The BSD-based version of echo concatenates all of the operands it is given and write them to standard output followed by a <newline>. If the -n option is present it doesn't output the <newline>. I assume this is the version of echo you have on your system. (On the UNIX System V-based version of echo -n is not an option; it is just another operand to be printed. But there are several escape sequences in the string operands that the System V echo will translate ("\t" -> <tab>, "\n" -> <newline>, "\0" -> skip the remainder of this and any following operand and skip the normal trailing <newline>, etc.) that the BSD echo will not change.) If you want to output some text without the normal trailing <newline> in a way that will be portable to all UNIX and Linux systems, use the printf utility instead of echo.

So, your cout << "string" being roughly equivalent to [icode]echo -n "string" is pretty close. But echo $1 is also an output statement; not an input statement. I'm more of a C guy, than C++. In C it is roughly equivalent to printf("%s\n", argv[1]);. The equivalence is would be exact if you used "$1" instead of $1 because if the string isn't quoted and you have the default setting for $IFS, any sequences of one or more <space> and <tab> characters will be translated to a single space and passed to the echo command as individual operands instead of as a single string.

In the shells (bash, ksh, sh, ...), $n (1 <= n <= 9) refers to the 9th argument given to to the shell script when it was invoked. If you use ${n}, n can be greater than 9. $0 refers to the name of the script (like argv[0] in a C or C++ program). So, if you have a regular file with the execute bit set named "script" that contains something like:
Code:
#!/bin/ksh
echo -n "There once was a "
echo $1
echo -n "that "
echo $2
echo -n "who liked to " 
echo $3
echo -n "There once was a " $1 " that " $2 " who liked to " $3

and invoked it as:
Code:
script man "spent a lot of time in a swimming pool" "win gold medals!"

the output should be something like:
Code:
There once was a man
 that spent a lot of time in a swimming pool
 who liked to win gold medals!
There once was a man that spent a lot of time in a swimming pool who liked to win gold medals!

 

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SDP(1)							    BSD General Commands Manual 						    SDP(1)

NAME
sdp -- scripting definition (sdef) processor SYNOPSIS
sdp -f {ahst} [-o directory | file | -] [options...] [file] DESCRIPTION
sdp transforms a scripting definition (``sdef'') file, or standard input if none is specified, into a variety of other formats for use with a scriptable application. The options are as follows: -f format Specify the output format. The format may be one or more of the following. Use these when you want to create a scriptable applica- tion: a Rez(1) input describing an 'aete' resource. s Cocoa Scripting ``.scriptSuite'' file. t Cocoa Scripting ``.scriptTerminology'' file. These formats are only necessary when creating a scriptable application that will run on Mac OS X 10.4 (Tiger) or earlier; as of 10.5 (Leopard), an application may use only an sdef. Use these when you want to control a scriptable application: h Scripting Bridge Objective-C header. You do not need to create a corresponding implementation file; Scripting Bridge will create the class implementations at runtime. -i includefile Include the type and class definitions from the specified sdef. It may be repeated to specify multiple files. This option is obso- lete; you should use an XInclude element in the sdef instead. -o directory | file | - Specify where to write the output. There are three styles: directory Write the output to automatically named files in that directory. Depending on the input and formats, sdp may generate several files. file Write all the output to that file. - Write all the output to standard output. The default is '-o .'; i.e., generate files in the current directory. Because Cocoa Scripting requires each suite to be in a separate file, using -o file with -f s or -f t is usually not a good idea. Some output formats have additional options relevant only to that format. For scriptSuite and scriptTerminology files (-f s and -f t): -V version Specify the minimum system version to be compatible with, for example, ``-V -10.4''. The default is to assume the current system ver- sion. Specifying anything before 10.3 will use NSString for 'file' type attributes, and will warn about non-object direct parameters. For Scripting Bridge Objective-C header files (-f h): --basename name, -N name Specify the ``base'' name. This name becomes the base name of the generated header and the prefix attached to all the generated classes. For example, saying --basename iTunes would result in a header file ``iTunes.h'' defining a iTunesApplication class. --hidden, -A Output definitions even for items the scripting definition marks as hidden. All such definitions will be flagged as deprecated, since hidden items are usually hidden for a reason. SEE ALSO
sdef(5) BUGS
sdp's error reporting leaves much to be desired. It does not provide line numbers for errors, though it will describe the element. It will not warn you of certain types of mistakes, such as using two different names with the same code (or vice versa), and will return a zero sta- tus even for erroneous input. Mac OS X July 12, 2007 Mac OS X
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