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Top Forums Shell Programming and Scripting Shell quoting rules for other languages programmers Post 302717219 by DGPickett on Wednesday 17th of October 2012 05:35:42 PM
Old 10-17-2012
I favor the use of the single quote for fastest and most certain processing, as it expands nothing. You can switch to double wuotes where you want expansion or a literal single quote, and then go back to single quoting. Since there is no expansion, there is less processing. For file wild card expansion, or globbing, you need to be outside quotes. I rather like a pipe: "echo '....' | command" over a here file: "command <<EOD
....
EOD" as I can predict and view expansions easily.

The eval I save for odd situations, like constructing a variable name from a varible and then fetching it. It is a shell built-in, so probably faster than `sh -c 'echo $x'"$m"`
 

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UUX(1C) 																   UUX(1C)

NAME
uux - unix to unix command execution SYNOPSIS
uux [ - ] command-string DESCRIPTION
Uux will gather 0 or more files from various systems, execute a command on a specified system and send standard output to a file on a spec- ified system. The command-string is made up of one or more arguments that look like a shell command line, except that the command and file names may be prefixed by system-name!. A null system-name is interpreted as the local system. File names may be one of(1) a full pathname; (2) a pathname preceded by ~xxx; where xxx is a userid on the specified system and is replaced by that user's login directory; (3) anything else is prefixed by the current directory. The `-' option will cause the standard input to the uux command to be the standard input to the command-string. For example, the command uux "!diff usg!/usr/dan/f1 pwba!/a4/dan/f1 > !fi.diff" will get the f1 files from the usg and pwba machines, execute a diff command and put the results in f1.diff in the local directory. Any special shell characters such as <>;| should be quoted either by quoting the entire command-string, or quoting the special characters as individual arguments. FILES
/usr/uucp/spool - spool directory /usr/uucp/* - other data and programs SEE ALSO
uucp(1) D. A. Nowitz, Uucp implementation description WARNING
An installation may, and for security reasons generally will, limit the list of commands executable on behalf of an incoming request from uux. Typically, a restricted site will permit little other than the receipt of mail via uux. BUGS
Only the first command of a shell pipeline may have a system-name!. All other commands are executed on the system of the first command. The use of the shell metacharacter * will probably not do what you want it to do. The shell tokens << and >> are not implemented. There is no notification of denial of execution on the remote machine. UUX(1C)
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