BitBarでPostgreSQLサーバーの状態を常に意識する ref: http://qiita.com/artifactsauce/items/445535ea8a58253c2f28

file0.txt

$ brew install postgresql
$ /usr/local/bin/initdb -D /usr/local/var/postgres
$ /usr/local/bin/pg_ctl -D /usr/local/var/postgres start
$ /usr/local/bin/createuser postgres

file2.txt

Start | bash=/usr/local/bin/pg_ctl param1=-D param2=$PGDATA param3=start refresh=true terminal=false

file3.txt

$ /usr/local/bin/psql -U postgres -w -q -A -F $'\x09' -c "select * from pg_stat_database;"
datid   datname numbackends     xact_commit     xact_rollback   blks_read       blks_hit        tup_returned    tup_fetched     tup_inserted    tup_updated     tup_deleted     conflicts       temp_files      temp_bytes      deadlocks       blk_read_time   blk_write_time stats_reset
1       template1       0       0       0       0       0       0       0       0       0       0       0       0       0       0      00
12636   template0       0       0       0       0       0       0       0       0       0       0       0       0       0       0      00
12641   postgres        1       6179    2       431     317062  1561344 123647  0       0       0       0       0       0       0      00       2016-10-31 20:33:03.144392+09
(3 rows)

file4.txt

$ /usr/local/bin/psql -U postgres -w -q -A -F $'\x09' -c "select * from pg_stat_database;" | perl -MData::Dumper -ne 'BEGIN { $_=<>; chomp; @headers = split "\t"} END { print Dumper \@headers }'
$VAR1 = [
          'datid',
          'datname',
          'numbackends',
          'xact_commit',
          'xact_rollback',
          'blks_read',
          'blks_hit',
          'tup_returned',
          'tup_fetched',
          'tup_inserted',
          'tup_updated',
          'tup_deleted',
          'conflicts',
          'temp_files',
          'temp_bytes',
          'deadlocks',
          'blk_read_time',
          'blk_write_time',
          'stats_reset'
        ];

file5.txt

$ /usr/local/bin/psql -U postgres -w -q -A -F $'\x09' -c "select * from pg_stat_database;" | perl -MData::Dumper -ne 'BEGIN { $_=<>; chomp; @headers = split "\t"} @records{@headers} = split "\t"; print Dumper \%records'
$VAR1 = {
          'blk_read_time' => '0',
          'xact_commit' => '0',
          'temp_files' => '0',
          'conflicts' => '0',
          'stats_reset' => '
',
          'tup_deleted' => '0',
          'xact_rollback' => '0',
          'numbackends' => '0',
          'tup_fetched' => '0',
(...)
          'tup_returned' => undef,
          'blk_write_time' => undef,
          'datid' => '(3 rows)
',
          'tup_inserted' => undef,
          'tup_updated' => undef,
          'datname' => undef,
          'deadlocks' => undef
        };

file6.pl

@record{@keys} = @values;

file7.txt

$ /usr/local/bin/psql -U postgres -w -q -A -F $'\x09' -c "select * from pg_stat_database;" | perl -MData::Dumper -nle 'BEGIN { $_=<>; chomp; @headers = split "\t"} last if eof(); @records{@headers} = split "\t"; next if $records{datname} =~/^template/; print Dumper \%records'
$VAR1 = {
          'tup_fetched' => '45296',
          'tup_updated' => '0',
          'temp_bytes' => '0',
          'tup_inserted' => '0',
          'tup_returned' => '565944',
          'datid' => '12641',
          'blks_read' => '239',
          'datname' => 'postgres',
          'deadlocks' => '0',
          'blk_write_time' => '0',
          'tup_deleted' => '0',
          'xact_commit' => '2209',
          'numbackends' => '1',
          'blk_read_time' => '0',
          'conflicts' => '0',
          'stats_reset' => '2016-11-09 01:06:07.773202+09',
          'blks_hit' => '116199',
          'temp_files' => '0',
          'xact_rollback' => '0'
        };

file8.pl

next if $records{datname} =~/^template/;

file9.pl

last if eof();

postgresql-status.1m.sh

#!/usr/bin/env bash
# <bitbar.title>PostgreSQL server status</bitbar.title>
# <bitbar.version>v1.0</bitbar.version>
# <bitbar.author>Kenji Akiyama</bitbar.author>
# <bitbar.author.github>artifactsauce</bitbar.author.github>
# <bitbar.desc>Show the status of PostgreSQL server installed by Homebrew on localhost and manage server boot with shortcut menus</bitbar.desc>
# <bitbar.image>http://i.imgur.com/l5E4yg8.png</bitbar.image>
# <bitbar.dependencies>bash,perl,postgresql</bitbar.dependencies>

# TODO Selecting some menus will return warnings because the process has not been completed.

set -eu

# Change here depending on your preference
MENUBAR_ICON_ENABLED=":elephant:"
MENUBAR_ICON_DISABLED=":sleepy:"
STATUS_ITEM_COLOR="green"
DISABLED_ITEM_COLOR="#C0C0C0"

# Below is no need to change basically.
SERVER_CMD="/usr/local/bin/pg_ctl"
PGDATA="/usr/local/var/postgres"

SUBCMD_START="start"
SUBCMD_STOP="stop"
SUBCMD_RESTART="restart"
SUBCMD_RELOAD="reload"
SUBCMD_STATUS="status"

if $SERVER_CMD -D $PGDATA $SUBCMD_STATUS | grep -Fq 'server is running'; then
  IS_SERVER_RUNNING=true
  echo "$MENUBAR_ICON_ENABLED"
else
  IS_SERVER_RUNNING=false
  echo "$MENUBAR_ICON_DISABLED"
fi

echo "---"
echo "PostgreSQL Server"

# Server Status from PostgreSQL's `pg_stat_database` table
if $IS_SERVER_RUNNING; then
  /usr/local/bin/psql -U postgres -w -q -A -F $'\x09' -c "select * from pg_stat_database;" | perl -nle 'BEGIN { $_=<>; chomp; @headers = split "\t"} last if eof(); @records{@headers} = split "\t"; next if $records{datname} =~/^template/; print "---"; print "$_: $records{$_} | color='$STATUS_ITEM_COLOR'" for @headers'
fi

# Server management shortcuts
echo "---"
if $IS_SERVER_RUNNING; then
  echo "Start | color=$DISABLED_ITEM_COLOR"
  echo "Stop | bash=$SERVER_CMD param1=-D param2=$PGDATA param4=$SUBCMD_STOP refresh=true terminal=false"
  echo "Restart | bash=$SERVER_CMD param1=-D param2=$PGDATA param4=$SUBCMD_RESTART refresh=true terminal=false"
  echo "Reload | bash=$SERVER_CMD param1=-D param2=$PGDATA param4=$SUBCMD_RELOAD refresh=true terminal=false"
else
  echo "Start | bash=$SERVER_CMD param1=-D param2=$PGDATA param4=$SUBCMD_START refresh=true terminal=false"
  echo "Stop | color=$DISABLED_ITEM_COLOR"
  echo "Restart | color=$DISABLED_ITEM_COLOR"
  echo "Reload | color=$DISABLED_ITEM_COLOR"
fi

echo "---"
echo "Refresh | refresh=true color=$DISABLED_ITEM_COLOR"