logcat: Adjust help to make it more meaningful

(cherry pick from commit 378f4745a27632f3bb26e7029fe55142001f3d47)

It is not clear about the long option aliases, list
them comma separate first for clarity. Squash lines
of help content if possible. Lock to 3 indents, one
for options, another for text on same line as options
and another for next line or continuation.

Bug: 28120456
Bug: 28788401
Bug: 28813587
Change-Id: I5331acde3ac0fd3b87f6699ba108f6cef46a1563
diff --git a/logcat/logcat.cpp b/logcat/logcat.cpp
index 37f4f4f..ca78930 100644
--- a/logcat/logcat.cpp
+++ b/logcat/logcat.cpp
@@ -278,61 +278,58 @@
     fprintf(stderr,"Usage: %s [options] [filterspecs]\n", cmd);
 
     fprintf(stderr, "options include:\n"
-                    "  -s              Set default filter to silent.\n"
-                    "                  Like specifying filterspec '*:S'\n"
-                    "  -f <filename>   Log to file. Default is stdout\n"
-                    "  --file=<filename>\n"
-                    "  -r <kbytes>     Rotate log every kbytes. Requires -f\n"
-                    "  --rotate-kbytes=<kbytes>\n"
-                    "  -n <count>      Sets max number of rotated logs to <count>, default 4\n"
-                    "  --rotate-count=<count>\n"
-                    "  -v <format>     Sets the log print format, where <format> is:\n"
-                    "  --format=<format>\n"
-                    "                      brief color epoch long monotonic printable process raw\n"
-                    "                      tag thread threadtime time uid usec UTC year zone\n\n"
-                    "  -D              print dividers between each log buffer\n"
-                    "  --dividers\n"
-                    "  -c              clear (flush) the entire log and exit\n"
-                    "  --clear\n"
-                    "  -d              dump the log and then exit (don't block)\n"
-                    "  -e <expr>       only print lines where the log message matches <expr>\n"
-                    "  --regex <expr>  where <expr> is a regular expression\n"
-                    "  -m <count>      quit after printing <count> lines. This is meant to be\n"
-                    "  --max-count=<count> paired with --regex, but will work on its own.\n"
-                    "  --print         paired with --regex and --max-count to let content bypass\n"
+                    "  -s              Set default filter to silent. Equivalent to filterspec '*:S'\n"
+                    "  -f <file>, --file=<file>               Log to file. Default is stdout\n"
+                    "  -r <kbytes>, --rotate-kbytes=<kbytes>\n"
+                    "                  Rotate log every kbytes. Requires -f option\n"
+                    "  -n <count>, --rotate-count=<count>\n"
+                    "                  Sets max number of rotated logs to <count>, default 4\n"
+                    "  -v <format>, --format=<format>\n"
+                    "                  Sets the log print format, where <format> is:\n"
+                    "                    brief color epoch long monotonic printable process raw\n"
+                    "                    tag thread threadtime time uid usec UTC year zone\n"
+                    "  -D, --dividers  Print dividers between each log buffer\n"
+                    "  -c, --clear     Clear (flush) the entire log and exit\n"
+                    "  -d              Dump the log and then exit (don't block)\n"
+                    "  -e <expr>, --regex=<expr>\n"
+                    "                  Only print lines where the log message matches <expr>\n"
+                    "                  where <expr> is a regular expression\n"
+                    // Leave --head undocumented as alias for -m
+                    "  -m <count>, --max-count=<count>\n"
+                    "                  Quit after printing <count> lines. This is meant to be\n"
+                    "                  paired with --regex, but will work on its own.\n"
+                    "  --print         Paired with --regex and --max-count to let content bypass\n"
                     "                  regex filter but still stop at number of matches.\n"
-                    "  -t <count>      print only the most recent <count> lines (implies -d)\n"
-                    "  -t '<time>'     print most recent lines since specified time (implies -d)\n"
-                    "  -T <count>      print only the most recent <count> lines (does not imply -d)\n"
-                    "  -T '<time>'     print most recent lines since specified time (not imply -d)\n"
+                    // Leave --tail undocumented as alias for -t
+                    "  -t <count>      Print only the most recent <count> lines (implies -d)\n"
+                    "  -t '<time>'     Print most recent lines since specified time (implies -d)\n"
+                    "  -T <count>      Print only the most recent <count> lines (does not imply -d)\n"
+                    "  -T '<time>'     Print most recent lines since specified time (not imply -d)\n"
                     "                  count is pure numerical, time is 'MM-DD hh:mm:ss.mmm...'\n"
                     "                  'YYYY-MM-DD hh:mm:ss.mmm...' or 'sssss.mmm...' format\n"
-                    "  -g              get the size of the log's ring buffer and exit\n"
-                    "  --buffer-size\n"
-                    "  -G <size>       set size of log ring buffer, may suffix with K or M.\n"
-                    "  --buffer-size=<size>\n"
-                    "  -L              dump logs from prior to last reboot\n"
-                    "  --last\n"
+                    "  -g, --buffer-size                      Get the size of the ring buffer.\n"
+                    "  -G <size>, --buffer-size=<size>\n"
+                    "                  Set size of log ring buffer, may suffix with K or M.\n"
+                    "  -L, -last       Dump logs from prior to last reboot\n"
                     // Leave security (Device Owner only installations) and
                     // kernel (userdebug and eng) buffers undocumented.
-                    "  -b <buffer>     Request alternate ring buffer, 'main', 'system', 'radio',\n"
-                    "  --buffer=<buffer> 'events', 'crash', 'default' or 'all'. Multiple -b\n"
-                    "                  parameters are allowed and results are interleaved. The\n"
-                    "                  default is -b main -b system -b crash.\n"
-                    "  -B              output the log in binary.\n"
-                    "  --binary\n"
-                    "  -S              output statistics.\n"
-                    "  --statistics\n"
-                    "  -p              print prune white and ~black list. Service is specified as\n"
-                    "  --prune         UID, UID/PID or /PID. Weighed for quicker pruning if prefix\n"
+                    "  -b <buffer>, --buffer=<buffer>         Request alternate ring buffer, 'main',\n"
+                    "                  'system', 'radio', 'events', 'crash', 'default' or 'all'.\n"
+                    "                  Multiple -b parameters are allowed. Buffers interleaved.\n"
+                    "                  Default -b main -b system -b crash.\n"
+                    "  -B, --binary    Output the log in binary.\n"
+                    "  -S, --statistics                       Output statistics.\n"
+                    "  -p, --prune     Print prune white and ~black list. Service is specified as\n"
+                    "                  UID, UID/PID or /PID. Weighed for quicker pruning if prefix\n"
                     "                  with ~, otherwise weighed for longevity if unadorned. All\n"
                     "                  other pruning activity is oldest first. Special case ~!\n"
                     "                  represents an automatic quicker pruning for the noisiest\n"
                     "                  UID as determined by the current statistics.\n"
-                    "  -P '<list> ...' set prune white and ~black list, using same format as\n"
-                    "  --prune='<list> ...'  printed above. Must be quoted.\n"
+                    "  -P '<list> ...', --prune='<list> ...'\n"
+                    "                  Set prune white and ~black list, using same format as\n"
+                    "                  listed above. Must be quoted.\n"
                     "  --pid=<pid>     Only prints logs from the given pid.\n"
-                    // Check ANDROID_LOG_WRAP_DEFAULT_TIMEOUT value
+                    // Check ANDROID_LOG_WRAP_DEFAULT_TIMEOUT value for match to 2 hours
                     "  --wrap          Sleep for 2 hours or when buffer about to wrap whichever\n"
                     "                  comes first. Improves efficiency of polling by providing\n"
                     "                  an about-to-wrap wakeup.\n");