如何從Shell腳本捕獲HBase Shell的輸出

Question

我需要從hbase shell獲取記錄並將其打印到下面的輸出文件中

while IFS="=" read name value
do
query=$(echo "get '/tables/${table_name}','${value}',{COLUMNS=>['cf2:CDC_TS','cf2:CDC_FLAG','cf:ROW_STS_CD']}" | hbase shell ) 
OUT=`tail "$query"`
echo "${OUT}" >> /results_${table_name}_${DATE_TIME}.txt
done < /Hbase_retrieve.properties

當我嘗試以上內容時

**

HBase Shell; enter 'help<RETURN>' for list of supported commands.
Type "exit<RETURN>" to leave the HBase Shell
Version 1.1.8-mapr-1710, r2c52ca3f992cced95f36b11d7b04b86474ad9ed0, Sun Nov 12 23:59:09 UTC 2017

Not all HBase shell commands are applicable to MapR tables.
Consult MapR documentation for the list of supported commands.

get '/tables/$table_name','row_key',{COLUMNS=>['cf2:CDC_TS','cf2:CDC_FLAG','cf:ROW_STS_CD']}
COLUMN  CELL
 cf:ROW_STS_CD timestamp=1506562033493, value=A
 cf2:CDC_FLAG timestamp=1506562033493, value=U
 cf2:CDC_TS timestamp=1506562033493, value=2017-09-27 20:27:13.493
3 row(s) in 0.1990 seconds

**

我如何消除那些和僅線條，並得到下面打印到輸出

get '/tables/$table_name','row_key',{COLUMNS=>['cf2:CDC_TS','cf2:CDC_FLAG','cf:ROW_STS_CD']}
COLUMN  CELL
 cf:ROW_STS_CD timestamp=1506562033493, value=A
 cf2:CDC_FLAG timestamp=1506562033493, value=U
 cf2:CDC_TS timestamp=1506562033493, value=2017-09-27 20:27:13.493

Answer 1

如果要將輸出寫入文件，但跳過第一部分（7行），則可以將tail用於該作業：

echo "${out}" | tail -n +7 >> /results_${table_name}_${DATE_TIME}.txt 

尾部的+號表示您不希望跳過N行。 從tail --help ：

-n, --lines=[+]NUM       output the last NUM lines, instead of the last 10;
                         or use -n +NUM to output starting with line NUM

---

編輯：哦，如果您也想刪除上一次：

echo "${out}" | tail -n +7 | head -n -1 >> /results_${table_name}_${DATE_TIME}.txt 

基本上是同一件事，反之亦然。 為了完整head --help ，請head --help ：

-n, --lines=[-]NUM       print the first NUM lines instead of the first 10;
                         with the leading '-', print all but the last
                         NUM lines of each file