Sponsored Content
Top Forums Shell Programming and Scripting getting full path from relative path Post 302110800 by Perderabo on Thursday 15th of March 2007 11:29:37 AM
Old 03-15-2007
Suppose that I don't have room in /usr for /usr/local but I do have some room in /export. So I make a directory called /export/usr.local and it has a subdirectory called bin. And I do a "ln -s /export/usr.local /usr/local". Now I do a "cd /usr/local" then I do a "cd bin". At this point my view is that I am in /usr/local/bin and a shell with a built-in pwd command may return that path. But /usr/bin/pwd will return /export/usr.local/bin. With more symbolic links in a path, there can be more aliases like this. The value returned by /usr/bin/pwd is the physical path. With good permissions on each directory leading to the current directory, /usr/bin/pwd can return the physical path. A built-in pwd in the same shell that navigated to the current directory may be able to return the particular logical path used to arrive at the current directory. Finding all logical paths to a particular directory would be rather daunting.

Writing a program like /usr/bin/pwd is not very easy in unix. You can stat the . directory to get the inode of the current directory. Then you can open .. and stat each file in the parent directory until you find the same inode. You walk up the chain one .. at a time repeating this process until . and .. are the same inode which means you have reached /. (Actually it is harder than that because you might traverse a mount point.) This is why putting an NFS mounted filesystem in / is very unwise... every /usr/bin/pwd must contact the NFS server to perform the stat.
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

vi - replacing a relative path with absolute path in a file

Hi, I have a file with about 60 lines of path: app-defaults/boxXYZ....... I want to change this to /my/path/goes/here/app-defaults/boxXYZ, but of course vi doesn't like the regualr :s/old/new/ command. Is there any other quick way to do this? Thanks ;) (2 Replies)
Discussion started by: Yinzer955i
2 Replies

2. UNIX for Dummies Questions & Answers

Help with absolute path and relative path

I'm having problems accessing the Knoppix software on my current computer and the replacement CD I ordered hasn't arrived yet. I have a guess at what the answer would be for this question but I am not sure as I cannot test it with the software. I have to create a directory called class, and... (1 Reply)
Discussion started by: mzero
1 Replies

3. Shell Programming and Scripting

how to read the relative path

suppose i ahve a shell script Nsdnet.sh inside a directory /dialp/Release/bin another file nsdnet_file.csv is under the same directory. Now in the shell script i have call a java file, which reads the csvfile from the commandline. Now when i run the file as $ ./Nsdnet.sh ./nsdnet_file.csv then... (5 Replies)
Discussion started by: priyanka3006
5 Replies

4. Shell Programming and Scripting

absolute path for a script ran with relative path

I have a script in which i want to print absolute path of the same script irrespective of path from where i run script. I am using test.sh: echo "pwd : `pwd`" echo "script name: $0" echo "dirname: `dirname $0`" when i run script from /my/test/dir/struct as ../test.sh the output i... (10 Replies)
Discussion started by: rss67
10 Replies

5. Shell Programming and Scripting

Retrieve directory path from full file path through sh

Hi, I have a file abcd.txt which has contents in the form of full path file names i.e. $home> vi abcd.txt /a/b/c/r1.txt /q/w/e/r2.txt /z/x/c/r3.txt Now I want to retrieve only the directory path name for each row i.e /a/b/c/ /q/w/e/ How to get the same through shell script?... (7 Replies)
Discussion started by: royzlife
7 Replies

6. Shell Programming and Scripting

How to extract strings from full path when full path is not fixed

/Path/snowbird9/nrfCompMgrRave1230100920.log.gz:09/20/2010 06:14:51 ERROR Error Message. /Path/snowbird6/nrfCompMgrRave1220100920.log.gz:09/20/2010 06:14:51 ERROR Error Message. /Path/snowbird14/nrfCompMgrRave920100920.log.gz:09/20/2010 06:14:51 ERROR Error Message.... (0 Replies)
Discussion started by: Shirisha
0 Replies

7. Shell Programming and Scripting

How to change Absolute path to Relative path

Hello, I have a doubt:- --------------------- Current script:- ################################################################################################ prefix=user@my-server: find . -depth -type d -name .git -printf '%h\0' | while read -d "" path ; do ( cd "$path" || exit $?... (4 Replies)
Discussion started by: sahil_jammu
4 Replies

8. UNIX for Dummies Questions & Answers

How to convert relative path to absolute path?

Hello Everyone, I want to convert Relative Path - /home/stevin/data/APP_SERVICE/../datafile.txt to Absolute Path - /home/stevin/data/datafile.txt Is there a built-in tool in Unix to do this or any good ideas as to how can I implement this. -Steve (5 Replies)
Discussion started by: qwarentine
5 Replies

9. Shell Programming and Scripting

Relative path not safe

Hallo everyone, I am running an SQL-Script over KShell-Script. Thus, in the KShell-Script there are these lines: WORKPATH=$PWD/work EXPORTDIR=export_meine_datei_bitte EXPORTPATH=${WORKPATH}/${EXPORTDIR} ... db2 connect to ${DBNAME} || die "can not open database connection" db2... (9 Replies)
Discussion started by: ratnalein88
9 Replies

10. UNIX for Beginners Questions & Answers

Convert Relative path to Absolute path, without changing directory to the file location.

Hello, I am creating a file with all the source folders included in my git branch, when i grep for the used source, i found source included as relative path instead of absolute path, how can convert relative path to absolute path without changing directory to that folder and using readlink -f ? ... (4 Replies)
Discussion started by: Sekhar419
4 Replies
Ns_Pathname(3aolserver) 				   AOLserver Library Procedures 				   Ns_Pathname(3aolserver)

__________________________________________________________________________________________________________________________________________________

NAME
Ns_HomePath, Ns_LibPath, Ns_MakePath, Ns_ModulePath, Ns_NormalizePath, Ns_PathIsAbsolute - Pathname procedures SYNOPSIS
#include "ns.h" char * Ns_HomePath(Ns_DString *dest, ...) char * Ns_LibPath(Ns_DString *dest, ...) char * Ns_MakePath(Ns_DString *dest, ...) char * Ns_ModulePath(Ns_DString *dest, char *server, char *module, ...) char * Ns_NormalizePath(Ns_DString *dsPtr, char *path) int Ns_PathIsAbsolute(char *path) _________________________________________________________________ DESCRIPTION
These functions operate on file pathnames. They work with Unix and Windows pathnames on their respective hosts. Ns_HomePath(dest, ...) Construct a path name relative to the home directory of the server. The full path is constructed by appending the library directory followed by each of the variable number of string elements after the dest argument. The elements will be separated by a / charac- ter. The list must be terminated with a NULL string. Ns_LibPath(dest, ...) Construct a path name relative to the library directory of the server, normally the lib/ subdirectory of the home directory. The full path is constructed by appending the library directory followed by each of the variable number of string elements after the dest argument. The elements will be separated by a / character. The list must be terminated with a NULL string. Ns_MakePath(dest, ...) Construct a path name from a list of path elements. The Ns_MakePath function constructs a path name by appending a list of path ele- ments to the given Ns_DString. The path elements are separated by single slashes, and the resulting path name is appended to the given Ns_DString. The last argument needs to be NULL to indicate the end of the argument list. Ns_ModulePath(dest, char *server, char *module, ...) Construct a server and/or module specific pathname relative to the server home directory. The path in constructed by first append- ing the server home directory. Next, if the server argument is not NULL, "server/servere appended to the destination and if the module argument is not NULL, "module/module" will be appended. Finally, all other string elements, if any, will be appended to the destination with separating / characters. The list must be terminated with a NULL string. Ns_NormalizePath(dsPtr, path) Normalize a path name. This function removes any extraneous slashes from the path and resolves "." and ".." references. The result is appended to the given Ns_DString. The following code appends "/dog" to the Ns_DString: Ns_NormalizePath(&ds, "/dog/cat/../../rat/../../dog//mouse/.."); Ns_PathIsAbsolute(path) Check for an absolute path name. Return NS_TRUE if the path is absolute and NS_FALSE otherwise. Under Unix, an absolute path starts with a "/". On Windows, it starts with a drive letter followed immediately by a ":". SEE ALSO
nsd(1), info(n) KEYWORDS
AOLserver 4.0 Ns_Pathname(3aolserver)
All times are GMT -4. The time now is 09:14 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy