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Top Forums Shell Programming and Scripting Use parameter expansion over a parameter expansion in bash. Post 303043406 by RavinderSingh13 on Tuesday 28th of January 2020 01:31:44 AM
Old 01-28-2020
Use parameter expansion over a parameter expansion in bash.

Hello All,

Could you please do help me here as I would like to perform parameter expansion in shell over a parameter expansion.

Let's say I have following variable.
Code:
path="/var/talend/nat/cdc"

Now to get only nat I could do following.
Code:
path1="${path%/*}"
path1="${path1##*/}"

Here in this approach I am creating a temporary variable path1 and again performing parameter expansion, how about if I want to perform this in single time without having temporary variable? I have tried it like:

Code:
echo "${((${path%/*}))##*/}"

Which is giving me an error. Any help, guidance is appreciated.

Thanks,
R. Singh
This User Gave Thanks to RavinderSingh13 For This Post:
 

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symlink(2)							System Calls Manual							symlink(2)

NAME
symlink - make symbolic link to a file SYNOPSIS
DESCRIPTION
The function creates a symbolic link. Its name is the pathname pointed to by path2, which must be a pathname that does not name an existing file or symbolic link. The contents of the symbolic link are the string pointed to by path1. RETURN VALUE
Upon successful completion, returns 0. Otherwise, it returns -1 and sets to indicate the error. ERRORS
If fails, is set to one of the following values: [EACCES] Write permission is denied in the directory where the symbolic link is being created, or search permission is denied for a component of the path prefix of path2. [EEXIST] The path2 argument names an existing file or symbolic link. [EFAULT] path1 or path2 points outside the process's allocated address space. The reliable detection of this error is implementation-dependent. [EIO] An I/O error occurred while reading from path1, making the directory entry for path2, allocating the inode for path2, or writing out the link contents of path2. [ELOOP] Too many symbolic links were encountered in resolving path2. [ENAMETOOLONG] The length of the path2 argument exceeds or pathname resolution of a symbolic link produced an intermediate result that exceeds or a pathname component is longer than [ENOENT] A component of path2 does not name an existing file or path2 is an empty string. [ENOSPC] The directory in which the entry for the new symbolic link is being placed cannot be extended because no space is left on the file system containing the directory, or the new symbolic link cannot be created because no space is left on the file system which will contain the link, or the file system is out of file- allocation resources. [ENOTDIR] A component of the path prefix of path2 is not a directory. [EROFS] The new symbolic link would reside on a read-only file system. APPLICATION USAGE
Like a hard link, a symbolic link allows a file to have multiple logical names. The presence of a hard link guarantees the existence of a file, even after the original name has been removed. A symbolic link provides no such assurance; in fact, the file named by the path1 argu- ment need not exist when the link is created. A symbolic link can cross file system boundaries. Normal permission checks are made on each component of the symbolic link pathname during its resolution. AUTHOR
was developed by the University of California, Berkeley. SEE ALSO
cp(1), chown(2), link(2), lstat(2), open(2), readlink(2), unlink(2), symlink(4), <unistd.h>. STANDARDS CONFORMANCE
CHANGE HISTORY
First released in Issue 4, Version 2. symlink(2)
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