if-conditionw在bash中带有“+”和“ - ”符号

Question

I and new to bash scripting and have tab-delimted text file with following columns

A234  +  -
B654  -  +
C630  +  +
D707  -  -

I would like to compare traverse every line of a file and compare second and third column to get an output like following in a text file

A234 Plus and Minus
B654 Minus and Plus
C630 Plus and Plus
D707 Minus and Minus

here is my bash script

#!/bin/bash
filename="$1"
while read line; 
do
g_symbol=$(echo $line | awk '{print $2}')
t_symbol=$(echo $line | awk '{print $3}')
if [[($g_symbol == "+") && ($t_symbol == "-")]]
then
echo $filename "PLus and Minus"
elif [[($g_symbol == "-") && ($t_symbol == "-")]]
then
echo $filename "Minus and Minus"
elif [[($g_symbol == "-") && ($t_symbol == "+")]]
then
echo $filename "Minus and Plus"
else
echo $filname "Plus and Plus"
fi
done < "$filename" 

But when I execute it, I get the following error

[[(+: command not found
[[(-: command not found
[[(-: command not found
[[(+: command not found

Kindly guide me.

Answer 1

It is easier to do using awk:

awk 'BEGIN{a["+"]="Plus"; a["-"]="Minus"} {print $1, a[$2], "and", a[$3]}' file

A234 Plus and Minus
B654 Minus and Plus
C630 Plus and Plus
D707 Minus and Minus

Answer 2

You don't need to run awk multiple times (or at all) to extract the fields from each line. Your error, though, is because you did not put whitespace around the [[ and ]] . Those are, despite containing nonalphabetic characters, keywords, not part of the if statement's syntax.

#!/bin/bash
filename="$1"
while IFS=$'\t' read first g_symbol t_symbol; 
do
  if [[ ($g_symbol == "+") && ($t_symbol == "-") ]]
  then
    echo $filename "PLus and Minus"
  elif [[ ($g_symbol == "-") && ($t_symbol == "-") ]]
  then
    echo $filename "Minus and Minus"
  elif [[ ($g_symbol == "-") && ($t_symbol == "+") ]]
  then
    echo $filename "Minus and Plus"
  else
    echo $filname "Plus and Plus"
  fi
done < "$filename" 

A case statement may be simpler:

#!/bin/bash
filename="$1"
while IFS=$'\t' read first g_symbol t_symbol; 
do
  case "$g_symbol $t_symbol" in
    "+ -") echo "$filename" "PLus and Minus" ;;
    "- -") echo "$filename" "Minus and Minus" ;;
    "- +") echo "$filename" "Minus and Plus" ;;
    "+ +") echo "$filname" "Plus and Plus" ;;
    *) echo "$filename" "Something else" ;;
  esac
done < "$filename" 

Answer 3

As mentioned in the comment, you'd better use sed or awk for this...

Here is an example using sed :

sed 's/\s*\([+-]\)\s*\([+-]\)/ \1 and \2/; # Add the ' and ' keyword and strip spaces
     s/\+/Plus/g;                          # Replace '+' by string 'Plus'
     s/-/Minus/g                           # Replace '-' by string 'Minus'
' file                     

Answer 4

Try this:

#!/bin/bash
filename="$1"
while read line; 
do
FirstColomn=$(echo $line | awk '{print $1}')
g_symbol=$(echo $line | awk '{print $2}')
t_symbol=$(echo $line | awk '{print $3}')
OutPutFileName="Output.txt"
if [[( $g_symbol == "+" ) && ( $t_symbol == "-" )]]
then
echo $FirstColomn" PLus and Minus" >>$OutPutFileName 
elif [[( $g_symbol == "-" ) && ( $t_symbol == "-") ]]
then
echo  $FirstColomn " Minus and Minus"  >>$OutPutFileName 
elif [[( $g_symbol == "-" ) && ( $t_symbol == "+" )]]
then
echo  $FirstColomn " Minus and Plus"  >>$OutPutFileName 
else
echo  $FirstColomn " Plus and Plus"  >>$OutPutFileName 
fi
done < $filename