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Top Forums Shell Programming and Scripting Bash variable delayed expansion? Post 302436039 by premotheus on Friday 9th of July 2010 04:42:23 AM
Old 07-09-2010
Bash variable delayed expansion?

i write a batch file , here is the content.
Code:
dirname='date +%Y-%m-%d'
mkdir dirname

but it doen's work, it just create a folder named date and +%Y-%m-%d.
i have tried run the command seperately in the bash prompt. after the first
sentence executed , i use $dirname to watch the value of dirname ,it's right.
but how come mkdir command doesn't work?
 

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DIRNAME(3)						   BSD Library Functions Manual 						DIRNAME(3)

NAME
dirname -- extract the directory part of a pathname SYNOPSIS
#include <libgen.h> char * dirname(char *path); DESCRIPTION
The dirname() function is the converse of basename(3); it returns a pointer to the parent directory of the pathname pointed to by path. Any trailing '/' characters are not counted as part of the directory name. If path is a null pointer, the empty string, or contains no '/' char- acters, dirname() returns a pointer to the string ".", signifying the current directory. IMPLEMENTATION NOTES
The dirname() function returns a pointer to internal storage space allocated on the first call that will be overwritten by subsequent calls. Other vendor implementations of dirname() may modify the contents of the string passed to dirname(); if portability is desired, this should be taken into account when writing code which calls this function. LEGACY SYNOPSIS
#include <libgen.h> char * dirname(const char *path); In legacy mode, path will not be changed. RETURN VALUES
On successful completion, dirname() returns a pointer to the parent directory of path. If dirname() fails, a null pointer is returned and the global variable errno is set to indicate the error. ERRORS
The following error codes may be set in errno: [ENAMETOOLONG] The path component to be returned was larger than MAXPATHLEN. SEE ALSO
basename(1), dirname(1), basename(3), compat(5) STANDARDS
The dirname() function conforms to X/Open Portability Guide Issue 4, Version 2 (``XPG4.2''). HISTORY
The dirname() function first appeared in OpenBSD 2.2 and FreeBSD 4.2. AUTHORS
Todd C. Miller BSD
October 12, 2006 BSD
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