How to Get the Directory from a File's Full Path

How do I get the directory from a file's full path?

If you've definitely got an absolute path, use Path.GetDirectoryName(path).

If you might only get a relative name, use new FileInfo(path).Directory.FullName.

Note that Path and FileInfo are both found in the namespace System.IO.

How to get full path of a file?

Use readlink:

readlink -f file.txt

How to extract directory path from file path?

dirname and basename are the tools you're looking for for extracting path components:

$ VAR='/home/pax/file.c'
$ DIR="$(dirname "${VAR}")" ; FILE="$(basename "${VAR}")"
$ echo "[${DIR}] [${FILE}]"
[/home/pax] [file.c]

They're not internal bash commands but they are part of the POSIX standard - see dirname and basename. Hence, they're probably available on, or can be obtained for, most platforms that are capable of running bash.

How do I get the absolute directory of a file in Bash?

To get the full path use:

readlink -f relative/path/to/file

To get the directory of a file:

dirname relative/path/to/file

You can also combine the two:

dirname $(readlink -f relative/path/to/file)

If readlink -f is not available on your system you can use this^*:

function myreadlink() {
  (
  cd "$(dirname $1)"         # or  cd "${1%/*}"
  echo "$PWD/$(basename $1)" # or  echo "$PWD/${1##*/}"
  )
}

Note that if you only need to move to a directory of a file specified as a relative path, you don't need to know the absolute path, a relative path is perfectly legal, so just use:

cd $(dirname relative/path/to/file)

if you wish to go back (while the script is running) to the original path, use pushd instead of cd, and popd when you are done.

* While myreadlink above is good enough in the context of this question, it has some limitation relative to the readlink tool suggested above. For example it doesn't correctly follow a link to a file with different basename.

How to get the directory of a file from the full path in C

What you're looking for is dirname(3). This is POSIX-only.

A Windows alternative would be _splitpath_s.

errno_t _splitpath_s(
   const char * path,
   char * drive,
   size_t driveNumberOfElements,
   char * dir,
   size_t dirNumberOfElements,
   char * fname,
   size_t nameNumberOfElements,
   char * ext, 
   size_t extNumberOfElements
);

Sample code (untested):

#include <stdlib.h>
const char* path = "C:\\some\\dir\\file";
char dir[256];

_splitpath_s(path,
    NULL, 0,             // Don't need drive
    dir, sizeof(dir),    // Just the directory
    NULL, 0,             // Don't need filename
    NULL, 0);

How can I extract the folder path from file path in Python?

You were almost there with your use of the split function. You just needed to join the strings, like follows.

>>> import os
>>> '\\'.join(existGDBPath.split('\\')[0:-1])
'T:\\Data\\DBDesign'

Although, I would recommend using the os.path.dirname function to do this, you just need to pass the string, and it'll do the work for you. Since, you seem to be on windows, consider using the abspath function too. An example:

>>> import os
>>> os.path.dirname(os.path.abspath(existGDBPath))
'T:\\Data\\DBDesign'

If you want both the file name and the directory path after being split, you can use the os.path.split function which returns a tuple, as follows.

>>> import os
>>> os.path.split(os.path.abspath(existGDBPath))
('T:\\Data\\DBDesign', 'DBDesign_93_v141b.mdb')

How to obtain the absolute path of a file via Shell (BASH/ZSH/SH)?

Use realpath

$ realpath example.txt
/home/username/example.txt

How do you get full paths of all files in a directory in Go?

If you want to see a full path, you should start with a full path. . is a relative path.

You can get the working path with os.Getwd

path, err := os.Getwd()
// handle err
printFiles(path)

The rest is simply appending the file name to the directory path. You should use the path/filepath package for that:

for _, file := range fileInfos {
    fmt.Println(filepath.Join(path, file.Name())
}