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AbdAllah Talaat's questions

Martin Hope
AbdAllah Talaat
Asked: 2019-06-30 06:24:38 +0800 CST
  • -1

我正在学习 bash 的启动文件，我找到了以下链接：

解释 bash 启动文件

然后在链接中图表的最后一个分支中，我发现如果 bash 是非登录非交互的，那么 env 变量应该来自环境变量 BASH_ENV ，我制作了一个测试文件并编写了 BASH_ENV="/home/myusername/ .bare.sh"

.bare.sh 的内容是：

var="the bare environment branch should be reached"

并启动了一个打印 var 的脚本：

echo $var

但启动脚本后没有输出

我希望它打印“应该到达裸环境分支”

这里可能是什么问题？

bash
Martin Hope
AbdAllah Talaat
Asked: 2018-03-16 05:09:39 +0800 CST
  • 0

我对使用的三种文档技术感到困惑，我有以下关于man，pinfo，/usr/share/doc的问题

  • man命令是否显示与pinfo相同的内容，只是它们显示信息的方式不同？或者它们在内容和获取文档的源目录上完全不同？

  • 是否有任何man或pinfo查找 pinfo 查找/usr/share/doc 或者它只是搜索已安装软件包信息的第三种方式

documentation
Martin Hope
AbdAllah Talaat
Asked: 2018-01-24 12:49:54 +0800 CST
  • 1

您好我正在尝试编写一个脚本来更新从文件中读取的行，到目前为止，除了下面提到的行之外，一切都运行良好

这是我的脚本：

#!/bin/bash     

#INITIALIZE PATHS
DB_PATH=${1}      
DATA_PATH="$DB_PATH/data/"
METADATA_PATH="$DB_PATH/metadata"   

#LOAD THE META DB FILE AND READ DATABASE NAME IN DB_NAME 
#READ ALSO COLUMNS IN AN ARRAY CALLED TABLE_NAMES                      
METADATA_LOAD=$(<"$METADATA_PATH/DB")
IFS=$'+'
read -a NAMES <<< "$METADATA_LOAD"



#PROMPET FOR TABLE TO UPDATE
echo ""
echo ""
echo ""
echo "You Currently Working with Database ${NAMES[0]}" 
echo ""
echo "You Have The Following Tables to Choose From :"
IFS=' '
for token in ${NAMES[@]:1}
do
echo "  $token"
done
echo ""
echo ""
echo ""
echo "Please Write The Name Of The Table You Want To Update :"
read CURRENT_TABLE


#Form META DATA TABLE FILE PATH
TABLE_DATA_PATH="$DB_PATH/data/$CURRENT_TABLE"
TABLE_METADATA_PATH="$DB_PATH/metadata/$CURRENT_TABLE"


#PROMPET WHICH COLUMN IS NEEDED TO CHECK FOR EQUALITY
echo ""
echo ""
echo ""
echo "The Table You Selected Have The Following Columns"
i=0 
TABLE_METADATA=$(<"$TABLE_METADATA_PATH")
IFS='+'
read -a CURRENT_TABLE_META <<< "$TABLE_METADATA"
IFS=' '
for token in ${CURRENT_TABLE_META[@]:1}
do
i=$(($i+1))
echo $i $token
done
echo "Please Enter The Number Column to Check For Equality"
read TEST_COLUMN_NUM
echo ""
echo ""
echo "Please Enter The Column Value to Check For Equality"
read TEST_COLUMN_VAL

echo "Please Enter The Column Number to Modify"
read MODIFY_COLUMN_NUM

echo "Please Enter The New Column Value"
read MODIFY_COLUMN_VAL

#Form DATA TABLE FILE PATH
TABLE_DATA=$(<"$TABLE_DATA_PATH") 


IFS=' '
read -a ROWS_ARRAY <<< "$TABLE_DATA"  




for CURRENT_ROW_INDEX in ${!ROWS_ARRAY[@]}
do

  IFS=':'
  read -a COLUMNS_ARRAY <<< "${ROWS_ARRAY[CURRENT_ROW_INDEX]}"

   for CURRENT_COL_INDEX in ${!COLUMNS_ARRAY[@]} 
   do

       if [[ ${COLUMNS_ARRAY[$CURRENT_COL_INDEX]} == $TEST_COLUMN_VAL  &&  $CURRENT_COL_INDEX -eq $(($TEST_COLUMN_NUM-1)) ]]
       then

           IFS=' '
           COLUMNS_ARRAY[$MODIFY_COLUMN_NUM] = "ABC"



       fi   

   done
done

我还没有完成脚本，但我在该行有一个错误：

 COLUMNS_ARRAY[$MODIFY_COLUMN_NUM] = "ABC"

它给了我错误

./更新：第 91 行：COLUMNS_ARRAY[3]：找不到命令

我想在给定索引处分配给数组以替换旧值，请帮助我了解错误原因以及如何解决

bash shell-script