permissions  number of hard links  owner name   group name   size in bytes   timestamp          file name
-rw-r--r--   2                      user         user         4096           Jul 25 13:54        test.dat

‘-l’
‘--format=long’
‘--format=verbose’
Produce long format. 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 (see Formatting file timestamps), normally the modification timestamp (the mtime, see File timestamps). If the owner or group name cannot be determined, print the owner or group ID instead, right-justified as a cue that it is a number rather than a textual name. Print question marks for other information that cannot be determined.

Normally the size is printed as a byte count without punctuation, but this can be overridden (see Block size). For example, --human-readable (-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 file system allocation for all files in that directory. The block size currently defaults to 1024 bytes, but this can be overridden (see 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)

‘l’
symbolic link

‘M’
off-line (“migrated”) file (Cray DMF)

‘n’
network special file (HP-UX)

‘p’
FIFO (named pipe)

‘P’
port (Solaris)

‘s’
socket

‘?’
some other file type

The file mode bits listed are similar to symbolic mode specifications (see 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. See Structure of File Mode Bits.

‘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 a security context, but no other alternate access method.

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

alias lsl='echo -e "Permissions\tLinks\t Owner\tGroup\tSize\tDate\tName";ls -l'

df  | tail -n +2