shell script 判斷grep字串是否有值

cat testfile.txt | grep -q 'JAMES'
if [ $? -ne 0 ]       #$?=0表示有找到值,1表示未找到, 2表示命令執行錯誤. ne=not eq
then
      echo "not find JAMES"
else
      echo "find JAMES"
fi

[PostgreSQL]TABLE LOCK查詢/解除

SELECT t.schemaname,
    t.relname,
    l.locktype,
    l.page,
    l.virtualtransaction,
    l.pid,
    l.mode,
    l.granted
   FROM pg_locks l
   JOIN pg_stat_all_tables t ON l.relation = t.relid
  WHERE t.schemaname <> 'pg_toast'::name AND t.schemaname <> 'pg_catalog'::name
  ORDER BY t.schemaname, t.relname;


  SELECT pg_cancel_backend('PID');