Извлечение имени файла из строки пути

В системах GNU это описано в ls информационная страница очень подробным способом. Все необходимо было сделать для нахождения его: просто открытый man ls и найдите в оконечном канале к полной документации: info coreutils 'ls invocation'.

Вот кавычка от него:

`-l'
`--format=long'
`--format=verbose'
     In addition to the name of each file, print the file type, file
     mode bits, number of hard links, owner name, group name, size, and
     timestamp (*note Formatting file timestamps::), normally the
     modification time.  Print question marks for information that
     cannot be determined.

     Normally the size is printed as a byte count without punctuation,
     but this can be overridden (*note Block size::).  For example, `-h'
     prints an abbreviated, human-readable count, and
     `--block-size="'1"' prints a byte count with the thousands
     separator of the current locale.

     For each directory that is listed, preface the files with a line
     `total BLOCKS', where BLOCKS is the total disk allocation for all
     files in that directory.  The block size currently defaults to 1024
     bytes, but this can be overridden (*note Block size::).  The
     BLOCKS computed counts each hard link separately; this is arguably
     a deficiency.

     The file type is one of the following characters:

    `-'
          regular file

    `b'
          block special file

    `c'
          character special file

    `C'
          high performance ("contiguous data") file

    `d'
          directory

    `D'
          door (Solaris 2.5 and up)

    `l'
          symbolic link

    `M'
          off-line ("migrated") file (Cray DMF)

    `n'
          network special file (HP-UX)

    `p'
          FIFO (named pipe)

    `P'
          port (Solaris 10 and up)

    `s'
          socket

    `?'
          some other file type

     The file mode bits listed are similar to symbolic mode
     specifications (*note Symbolic Modes::).  But `ls' combines
     multiple bits into the third character of each set of permissions
     as follows:

    `s'
          If the set-user-ID or set-group-ID bit and the corresponding
          executable bit are both set.

    `S'
          If the set-user-ID or set-group-ID bit is set but the
          corresponding executable bit is not set.

    `t'
          If the restricted deletion flag or sticky bit, and the
          other-executable bit, are both set.  The restricted deletion
          flag is another name for the sticky bit.  *Note Mode
          Structure::.

    `T'
          If the restricted deletion flag or sticky bit is set but the
          other-executable bit is not set.

    `x'
          If the executable bit is set and none of the above apply.

    `-'
          Otherwise.

     Following the file mode bits is a single character that specifies
     whether an alternate access method such as an access control list
     applies to the file.  When the character following the file mode
     bits is a space, there is no alternate access method.  When it is
     a printing character, then there is such a method.

     GNU `ls' uses a `.' character to indicate a file with an SELinux
     security context, but no other alternate access method.

     A file with any other combination of alternate access methods is
     marked with a `+' character.