core/commands/unixfs: Rename 'ipfs unixfs' to 'ipfs file'

To be less confusing to newcomers (the IPFS filesystem isn't
Unix-specific anyway, and it isn't even very POSIX-specific [1,2,3]).
I'm a bit uncertain about having one name for users and another for
devs, but the consensus seems to be that mainaining two names is worth
the trouble [4].  We also kicked around:

* 'files' (plural),
* 'filesystem' (too long), and
* 'fs' (redundant after 'ipfs', even though IPFS isn't just about
  filesystems)

on IRC [5 through 6].  I wish there was a more evocative term.  I'm
never sure where "file" lands on the scale between "filesysytem",
"everything is a file", "a single chunk of data with an associated
inode".  But we can't think of anything better.

[1]: #1348 (comment)
[2]: #1348 (comment)
[3]: https://github.com/ipfs/go-ipfs/pull/1136/files#r29377283
  In my response to this (no longer visibile on GitHub):

  On Wed, Apr 29, 2015 at 01:30:04PM -0700, Juan Batiz-Benet wrote:
  > > +package fsnode
  >
  > i think this package should be called `unixfs` as that's the
  > abstraction that this is calling to.

  Will do, although I don't see what's especially Unix-y about these
  file nodes.

[4]: #1348 (comment)
[5]: https://botbot.me/freenode/ipfs/2015-06-09/?msg=41428456&page=5
[6]: https://botbot.me/freenode/ipfs/2015-06-09/?msg=41430703&page=5

core/commands/root.go

@@ -36,7 +36,7 @@ DATA STRUCTURE COMMANDS
 
     block         Interact with raw blocks in the datastore
     object        Interact with raw dag nodes
-    unixfs        Interact with Unix filesystem objects
+    file          Interact with Unix filesystem objects
 
 ADVANCED COMMANDS
 
@@ -104,7 +104,7 @@ var rootSubcommands = map[string]*cmds.Command{
 	"stats":     StatsCmd,
 	"swarm":     SwarmCmd,
 	"tour":      tourCmd,
-	"unixfs":    unixfs.UnixFSCmd,
+	"file":      unixfs.UnixFSCmd,
 	"update":    UpdateCmd,
 	"version":   VersionCmd,
 	"bitswap":   BitswapCmd,

core/commands/unixfs/unixfs.go

@@ -6,12 +6,12 @@ var UnixFSCmd = &cmds.Command{
 	Helptext: cmds.HelpText{
 		Tagline: "Interact with ipfs objects representing Unix filesystems",
 		ShortDescription: `
-'ipfs unixfs' provides a familar interface to filesystems represtented
+'ipfs file' provides a familar interface to filesystems represtented
 by IPFS objects that hides IPFS-implementation details like layout
 objects (e.g. fanout and chunking).
 `,
 		Synopsis: `
-ipfs unixfs ls <path>...  - List directory contents for <path>...
+ipfs file ls <path>...  - List directory contents for <path>...
 `,
 	},
 

test/sharness/t0200-unixfs-ls.sh

@@ -4,7 +4,7 @@
 # MIT Licensed; see the LICENSE file in this repository.
 #
 
-test_description="Test unixfs ls command"
+test_description="Test file ls command"
 
 . lib/test-lib.sh
 
@@ -38,11 +38,11 @@ test_ls_cmd() {
 		test_cmp expected_add actual_add
 	'
 
-	test_expect_success "'ipfs unixfs ls <three dir hashes>' succeeds" '
-		ipfs unixfs ls QmfNy183bXiRVyrhyWtq3TwHn79yHEkiAGFr18P7YNzESj QmR3jhV4XpxxPjPT3Y8vNnWvWNvakdcT3H6vqpRBsX1MLy QmSix55yz8CzWXf5ZVM9vgEvijnEeeXiTSarVtsqiiCJss >actual_ls
+	test_expect_success "'ipfs file ls <three dir hashes>' succeeds" '
+		ipfs file ls QmfNy183bXiRVyrhyWtq3TwHn79yHEkiAGFr18P7YNzESj QmR3jhV4XpxxPjPT3Y8vNnWvWNvakdcT3H6vqpRBsX1MLy QmSix55yz8CzWXf5ZVM9vgEvijnEeeXiTSarVtsqiiCJss >actual_ls
 	'
 
-	test_expect_success "'ipfs unixfs ls <three dir hashes>' output looks good" '
+	test_expect_success "'ipfs file ls <three dir hashes>' output looks good" '
 		cat <<-\EOF >expected_ls &&
 			QmfNy183bXiRVyrhyWtq3TwHn79yHEkiAGFr18P7YNzESj:
 			QmSix55yz8CzWXf5ZVM9vgEvijnEeeXiTSarVtsqiiCJss Directory 246  d1
@@ -61,11 +61,11 @@ test_ls_cmd() {
 		test_cmp expected_ls actual_ls
 	'
 
-	test_expect_success "'ipfs unixfs ls --headers <three dir hashes>' succeeds" '
-		ipfs unixfs ls --headers QmfNy183bXiRVyrhyWtq3TwHn79yHEkiAGFr18P7YNzESj QmR3jhV4XpxxPjPT3Y8vNnWvWNvakdcT3H6vqpRBsX1MLy QmSix55yz8CzWXf5ZVM9vgEvijnEeeXiTSarVtsqiiCJss >actual_ls_headers
+	test_expect_success "'ipfs file ls --headers <three dir hashes>' succeeds" '
+		ipfs file ls --headers QmfNy183bXiRVyrhyWtq3TwHn79yHEkiAGFr18P7YNzESj QmR3jhV4XpxxPjPT3Y8vNnWvWNvakdcT3H6vqpRBsX1MLy QmSix55yz8CzWXf5ZVM9vgEvijnEeeXiTSarVtsqiiCJss >actual_ls_headers
 	'
 
-	test_expect_success "'ipfs unixfs ls --headers <three dir hashes>' output looks good" '
+	test_expect_success "'ipfs file ls --headers <three dir hashes>' output looks good" '
 		cat <<-\EOF >expected_ls_headers &&
 			QmfNy183bXiRVyrhyWtq3TwHn79yHEkiAGFr18P7YNzESj:
 			Hash                                           Type      Size Name
@@ -87,11 +87,11 @@ test_ls_cmd() {
 		test_cmp expected_ls_headers actual_ls_headers
 	'
 
-	test_expect_success "'ipfs unixfs ls <file hashes>' succeeds" '
-		ipfs unixfs ls /ipfs/QmR3jhV4XpxxPjPT3Y8vNnWvWNvakdcT3H6vqpRBsX1MLy/1024 QmQNd6ubRXaNG6Prov8o6vk3bn6eWsj9FxLGrAVDUAGkGe >actual_ls_file
+	test_expect_success "'ipfs file ls <file hashes>' succeeds" '
+		ipfs file ls /ipfs/QmR3jhV4XpxxPjPT3Y8vNnWvWNvakdcT3H6vqpRBsX1MLy/1024 QmQNd6ubRXaNG6Prov8o6vk3bn6eWsj9FxLGrAVDUAGkGe >actual_ls_file
 	'
 
-	test_expect_success "'ipfs unixfs ls <file hashes>' output looks good" '
+	test_expect_success "'ipfs file ls <file hashes>' output looks good" '
 		cat <<-\EOF >expected_ls_file &&
 			QmbQBUSRL9raZtNXfpTDeaxQapibJEG6qEY8WqAN22aUzd File 1024 /ipfs/QmR3jhV4XpxxPjPT3Y8vNnWvWNvakdcT3H6vqpRBsX1MLy/1024
 			QmQNd6ubRXaNG6Prov8o6vk3bn6eWsj9FxLGrAVDUAGkGe File 128  QmQNd6ubRXaNG6Prov8o6vk3bn6eWsj9FxLGrAVDUAGkGe