Question

我正在尝试使用以下代码来读取用户的变量;要搜索的文件，搜索字符串，输出所需的空格以及要输出的字段数量。

第一个问题是使用AWK命令。如果我输入一个有效的空格，例如“”（单个空格“或”\ t“），我会收到未终止的字符串和语法错误，只有在我请求输出多个字段时才会出现错误（否则不会添加空格）上）。

其次GREP在使用搜索字符串时似乎有点挑剔。我必须在变量的开头和结尾添加双引号，以便使用整个字符串。

#!/bin/bash
#****************************************************
#Name:          reportCreator.sh
#Purpose:       Create reports from log files
#Author:        
#Date Written:      11/01/2013
#Last Updated:      11/01/2013
#****************************************************

clear

#Determine what to search for
printf "Please enter input file name(s): "
read inputFile
printf "Please enter your search query: "
read searchQuery
printf "Please enter the whitespace character: "
IFS= read whitespace
printf "Please enter the amount of fields to be displayed: "
read fieldAmount

#Add quotation marks to whitespace and searchQuery
whitespace=\""$whitespace"\"
searchQuery=\""$searchQuery"\"

#Declare variables
declare -i counter=0
declare -a fields[$fieldAmount]
declare -a fieldInsert[$fieldAmount]

#While loop for entering fields
while [[ "$counter" -ne "$fieldAmount" ]]
do
        #Ask for field numbers
        printf "Please enter number for required field $((counter+1)): "
        read fields[$counter]
        ((counter++))
done

#Create function to add '$' before every field and the whitespace characters
function fieldFunction 
{
    for (( counter=0; counter <= ($fieldAmount-1); counter++ ))
    do
        fieldInsert[$fieldAmount]="$""${fields[$counter]}"
        if (( counter!=($fieldAmount-1) ))
        then
            printf "${fieldInsert[*]}$whitespace"
        else
            printf "${fieldInsert[*]}"
        fi  
    done
}
printf "%b\n"

tac $inputFile | grep "$searchQuery" | less #| awk '{print $(fieldFunction)}'

exit 0

任何帮助都将不胜感激。

Answer 1

Grep不理解引号，因此请删除将它们添加到$ searchQuery的行。
对awk使用双引号而不是单引号，因此$（fieldFunction）将展开。

解决这个问题（当然还有取消注释awk），它可以工作：

user@host 15:00 ~ $ cat script
#!/bin/bash
#****************************************************
#Name:          reportCreator.sh
#Purpose:       Create reports from log files
#Author:        
#Date Written:      11/01/2013
#Last Updated:      11/01/2013
#****************************************************

clear

#Determine what to search for
printf "Please enter input file name(s): "
read inputFile
printf "Please enter your search query: "
read searchQuery
printf "Please enter the whitespace character: "
IFS= read whitespace
printf "Please enter the amount of fields to be displayed: "
read fieldAmount

#Add quotation marks to whitespace and searchQuery
whitespace=\""$whitespace"\"

#Declare variables
declare -i counter=0
declare -a fields[$fieldAmount]
declare -a fieldInsert[$fieldAmount]

#While loop for entering fields
while [[ "$counter" -ne "$fieldAmount" ]]
do
        #Ask for field numbers
        printf "Please enter number for required field $((counter+1)): "
        read fields[$counter]
        ((counter++))
done

#Create function to add '$' before every field and the whitespace characters
function fieldFunction
{
    for (( counter=0; counter <= ($fieldAmount-1); counter++ ))
    do
        fieldInsert[$fieldAmount]="$""${fields[$counter]}"
        if (( counter!=($fieldAmount-1) ))
        then
            printf "${fieldInsert[*]}$whitespace"
        else
            printf "${fieldInsert[*]}"
        fi
    done
}
printf "%b\n"

tac $inputFile | grep "$searchQuery" | awk "{print $(fieldFunction)}"

exit 0
user@host 15:01 ~ $ cat file
foo two three four
foo two2 three2 four2
bar two three four
user@host 15:01 ~ $ bash script
Please enter input file name(s): file
Please enter your search query: foo
Please enter the whitespace character:
Please enter the amount of fields to be displayed: 2
Please enter number for required field 1: 4
Please enter number for required field 2: 2

four2   two2
four    two
user@host 15:01 ~ $

Answer 2

让我们来看看这部分代码：

#Create function to add '$' before every field and the whitespace characters
function fieldFunction
{
    for (( counter=0; counter <= ($fieldAmount-1); counter++ ))
    do
        fieldInsert[$fieldAmount]="$""${fields[$counter]}"
        if (( counter!=($fieldAmount-1) ))
        then
            printf "${fieldInsert[*]}$whitespace"
        else
            printf "${fieldInsert[*]}"
        fi
    done
}
printf "%b\n"

tac $inputFile | grep "$searchQuery" | awk "{print $(fieldFunction)}"

它可以更简单，更健壮地重写（未经测试）：

tac "$inputFile" |
awk -v fieldsStr="${fields[*]}" -v searchQuery="$searchQuery" -v OFS="$whitespace" '
   BEGIN{ numFields = split(fieldsStr,fieldsArr) }
   $0 ~ searchQuery {
      for ( i=1; i <= numFields; i++ )
         printf "%s%s", (i==1?"":OFS), $(fieldsArr[i])
      print "\b"
   }
'

我不知道为什么你需要“tac”打开文件，但我认为你有理由让我把它留下来。

Bash的未终止字符串/语法错误

2 个答案: