When creating filepaths and URLs, I noticed that many times the path starts with ./ or ~/.
What is the difference between filepaths that start with ./ and ~/?
What do each of them mean?
For the sake of completeness ...
Just path is a file or directory named path in the current directory.
./path is a file or directory named path in the current directory, with the directory spelled out. The dot directory . represents the current directory, and path is the name of the file or directory within this directory.
~/path is a shorthand for $HOME/path where $HOME is a variable which refers to your home directory. Typically your home directory will be somewhere like /home/you or /Users/you where you is your account name. (The command echo "$HOME" will display your home directory.) The expanded value is an absolute path (unless you have messed up the value of $HOME thoroughly), as indicated by the initial slash.
/path is an absolute path which refers to a file or directory named path which is in the root directory /. Every file on Unix is ultimately somewhere in the directory tree which starts with the root directory.
A file name which begins with $ includes the value of a shell variable in its name (like for example $HOME above); you have to know the value of that variable to determine whether it ends up containing a relative or an absolute path. Similarly, ~ at the beginning of a file name gets replaced ("expanded") by the shell to a different string, as outlined above.
(Technically, it's possible for a file name to begin with a literal dollar sign or tilde, too; you would then have to quote or backslash-escape that character to avoid having the shell expand it to something else. This is rather inconvenient, so these file names tend to be rare in practice.)
In the following exposition, we refer to the result of any such replacements, and ignore the complication of possible quoting.
Every file name which begins with / is an absolute path (aka full path) which explains how to reach a particular node starting from the root directory. For example, /var/tmp/you/reminder.txt refers to a file or directory reminder.txt (probably a file, judging from the name; but Unix doesn't care what you call your files or directories) which is in the directory you which is in the directory tmp which is in the directory var which is in the root directory.
Every file name which doesn't begin with / is a relative path which indicates how to reach a particular file or directory starting from the current directory. The special directory .. is the parent directory (that is, the directory which contains this directory) and the special directory . is the current directory. So path/there refers to the file or directory there inside the directory path in the current directory; and (hover the mouse over the gray area to display the spoiler)
there/.././and/back/.. is a (wicked complicated) way to refer to the directory and in the current directory, where we traverse the there directory and then move back to the current directory; then stay in the current directory; then refer to the directory back inside the directory and, but then move back to the parent directory of that, ending up with ./and.
In addition to ~/ for the current user's home directory, some shells and applications allow the notation ~them/ to refer to the home directory of the user account them. Also, some web server configurations allow each user to have a public web site in their directory ~/public_html and the URL notation http://server/~them/ would serve up the site of the user account them for outside visitors.
The current directory is a convenience which the shell provides so you don't have to type long paths all the time. You can, if you want to.
/bin/ls /home/you/Documents/unix-101/directories.txt
is a longwinded but perfectly valid way to say (assuming you are in your home directory),
ls Documents/unix-101/directories.txt
You could also say
cd Documents/unix-101
ls directories.txt
and until you cd again, all your commands will run in this directory.
See What exactly is current working directory? for a longer exposition of this related concept.
A "directory" is sometimes called a "folder" by people who are not yet old enough to prefer the former.
Tangentially, don't confuse the directory name . with the Bourne shell command which comprises a single dot (also known by its Bash alias source). The command
. ./scriptname
runs the commands from the file ./scriptname in the context of the current shell instance, as opposed to in a separate subshell (which is what just ./scriptname does). In other words, this command line invokes the dot command on a file scriptname in the dot directory.
The Bourne shell (and derivatives like Bash, Zsh, etc) use single quotes to prevent variable expansion and wildcard expansion, and double quotes to permit variable expansion, but inhibit wildcard expansion in a string. The quoting rules on Windows are different, and generally use double quotes to keep whitespace-separated values as a single string (and % instead of $ for variable substitutions).
./ means "starting from the current directory". . refers to the current working directory, so something like ./foo.bar would be looking for a file called foo.bar in the current directory. (As a side note, .. means refers to the parent directory of the current directory. So ../foo.bar would be looking for that file one directory above.)
~/ means "starting from the home directory". This could have different meanings in different scenarios. For example, in a Unix environment ~/foo.bar would be looking for a file called foo.bar in your home directory, something like /home/totzam/foo.bar. In many web applications, ~/foo.bar would be looking for a file called foo.bar in the web application root, something like /var/http/mywebapp/foo.bar.
./ is the current directory
~/ is the home directory of the current user
./ means that path is relative to your current position.
~/ means that path is relative to your home directory.
I will explain a simple example of it. As developers mentioned:
./ is current directory.
~/ is the home directory of the current user.
How both of the file path expressions can help us? Suppose you want to execute a script (.sh) and you're in the same directory where file exists then you can simply do it ./filename.sh
I mostly use ~/ to access my home directory files like .bashrc when I want to add any config in it. It's easier since the file path expression (for home directory) feels much easier and makes accessibility to the file from anywhere, without worrying about the path or changing the path.
. represents current directory
.. represents the parent directory
~ represents the home directory for the current user. Home directory is also represented by HOME env variable. you can do echo $HOME on the shell to see it.
These are generally used to specify relative paths. The / in the end of each notation is a separator that you can use when using these notations together.
Ex:
$ cd ../.. # Go 2 directories backwards
$ cd ~ # Takes you to $HOME directory
$ cd . # Does nothing :) As it literally means go to the directory that you are already present in.
$ cd ~/dir1 $ go to `$HOME/dir1`
On Unix, in any directory if you do ls -a you would see that . and .. will be mentioned (even for empty directory). Like mentioned, these have special meaning and are generated by default in Unix systems and are generally helpful to specify relative paths (i.e, path to a different directory relative to your current directory)
cd command is harmless. So, just play around by combining notations with cd command. You will eventually get a grip of them.
Using any of the standard Robot libraries, is it possible to recursively copy the contents of a directory to an existing destination directory?
Basically, I'm looking for the equivalent of the following shell command: cp -r foo/. bar (note the trailing dot)
I tried Copy Directory but this creates a directory foo inside bar (as documented) and it doesn't stop doing that even when supplying the trailing dot. Copy Files chokes when it encounters a directory.
Is there anything I overlooked? Or do I need to just call cp -r myself?
As I only need this to work on Linux, I ended up implementing a custom keyword calling cp -r. If this is ever needed cross-platform, then I'll follow the suggestions to directly implement it in Python.
Copy Directory Contents
[Documentation] Recursively copies the contents of the source directory into the destination.
[Arguments] ${source} ${destination}
Directory Should Exist ${source}
Directory Should Exist ${destination}
${result} = Run Process cp -r ${source}/. ${destination}/
Should Be Equal As Integers ${result.rc} 0
OwinHost.exe seems to only want to run against an application that lives in a folder called "bin". If I try against another folder e.g. "bin2", OwinHost says that it can't find the startup attribute.
I've tried running from within the bin2 folder, outside it, and tried the -d and -b arguments - nothing seems to work.
Prolog: I'm an idiot for missing this in the documentation
cmake-2.8.10.2
How do you make cmake preserve the original file permissions when installing a directory? For the project at hand, I'd like it to essentially copy some directories from my source tree to the install tree. To wit:
install(
DIRECTORY config runp
DESTINATION ${CMAKE_INSTALL_PREFIX}
PATTERN ".svn" EXCLUDE
PATTERN ".git" EXCLUDE
PATTERN "start_collection.snl" EXCLUDE
)
All works as expected -- except that executable scripts are getting copied in with incorrect file permissions. In fact, none of the original file permissions are preserved. Globally setting permissions using FILE_PERMISSIONS and DIRECTORY_PERMISSIONS is something I do not want to do, and frankly, would be a hack in this context.
In the shell-scripting world, I'd do something simple like this:
for i in config runp ; do
tar cf - $i | tar -C $CMAKE_INSTALL_PREFIX -xf -
done
Documentation suggests using USE_SOURCE_PERMISSIONS when calling install():
install(
DIRECTORY config runp
DESTINATION ${CMAKE_INSTALL_PREFIX}
USE_SOURCE_PERMISSIONS
PATTERN ".svn" EXCLUDE
PATTERN ".git" EXCLUDE
PATTERN "start_collection.snl" EXCLUDE
)
Alternatively, you can use install(PROGRAMS signature of this command. See docs for more info.
We are deploying a website to a DFS share. DFS creates shortcut files with the name .DFSFolderLink.lnk in various locations. Admins on the box do not have rights to delete this shortcut file. So if any exist I need to exclude them from deployment, so that they will not be deleted.
I can already exclude the .DFSFolderLink by passing -skip:File=.DFSFolderLink.lnk to msdeploy. However, if the directory that contains the shortcut file does not exist in the package being deployed, then an error is raised because it tries to delete the folder but cannot because the shortcut file still exists.
How can I get it to exclude the shortcut file and the directory that contains it without knowing ahead of time what the directory name is?
If you don't know the name of the directory, you can't skip it. What you can do is tell msdeploy to ignore the "directory not empty" error using the ignoreErrors provider setting:
msdeploy -verb:sync -source:... ^
-dest:auto,ignoreErrors=80070091,computerName=... ^
-skip:File=\.DFSFolderLink.lnk