Shell 脚本未在输入文本文件时运行

Question

I am solving something using mapper shell script. I have created two files

mr_test.txt

we will see how map reduce works for word count problem. word count is considered as hello world of map reduce programming. this program will not print hello world instead it will give word counts. lets see map reduce in action.

and another shell script called

mapper.sh

while read line; do
  for token in $line; do
    if ["$token" = "hello" ]; then 
      echo "hello,1"
    elif ["$token" = "world"]; then 
      echo "world,1"
    fi
  done
done

I am looking out here to print all the hello and world present in my txt document using the shell script. Now I enter the following commands

chmod +x mapper.sh

later followed by

cat mr_test.txt | ./mapper.sh

I get the output as

./mapper.sh: line 5: [hello: command not found
./mapper.sh: line 8: [hello: command not found
./mapper.sh: line 5: $'[everyone,\r': command not found
./mapper.sh: line 8: $'[everyone,\r': command not found
./mapper.sh: line 5: [we: command not found
./mapper.sh: line 8: [we: command not found
./mapper.sh: line 5: [will: command not found
./mapper.sh: line 8: [will: command not found
./mapper.sh: line 5: [see: command not found
./mapper.sh: line 8: [see: command not found
./mapper.sh: line 5: [how: command not found
./mapper.sh: line 8: [how: command not found
./mapper.sh: line 5: [map: command not found
./mapper.sh: line 8: [map: command not found
./mapper.sh: line 5: [reduce: command not found
./mapper.sh: line 8: [reduce: command not found
./mapper.sh: line 5: [works: command not found
./mapper.sh: line 8: [works: command not found
./mapper.sh: line 5: [for: command not found
./mapper.sh: line 8: [for: command not found
./mapper.sh: line 5: [word: command not found
./mapper.sh: line 8: [word: command not found
./mapper.sh: line 5: [count: command not found
./mapper.sh: line 8: [count: command not found
./mapper.sh: line 5: [problem.: command not found
./mapper.sh: line 8: [problem.: command not found
./mapper.sh: line 5: [word: command not found
./mapper.sh: line 8: [word: command not found
./mapper.sh: line 5: [count: command not found
./mapper.sh: line 8: [count: command not found
./mapper.sh: line 5: [is: command not found
./mapper.sh: line 8: [is: command not found
./mapper.sh: line 5: [considered: command not found
./mapper.sh: line 8: [considered: command not found
./mapper.sh: line 5: [as: command not found
./mapper.sh: line 8: [as: command not found
./mapper.sh: line 5: [hello: command not found
./mapper.sh: line 8: [hello: command not found
./mapper.sh: line 5: [world: command not found
./mapper.sh: line 8: [world: command not found
./mapper.sh: line 5: [of: command not found
./mapper.sh: line 8: [of: command not found
./mapper.sh: line 5: [map: command not found
./mapper.sh: line 8: [map: command not found
./mapper.sh: line 5: [reduce: command not found
./mapper.sh: line 8: [reduce: command not found
./mapper.sh: line 5: [programming.: command not found
./mapper.sh: line 8: [programming.: command not found
./mapper.sh: line 5: [this: command not found
./mapper.sh: line 8: [this: command not found
./mapper.sh: line 5: [program: command not found
./mapper.sh: line 8: [program: command not found
./mapper.sh: line 5: [will: command not found
./mapper.sh: line 8: [will: command not found
./mapper.sh: line 5: [not: command not found
./mapper.sh: line 8: [not: command not found
./mapper.sh: line 5: [print: command not found
./mapper.sh: line 8: [print: command not found
./mapper.sh: line 5: [hello: command not found
./mapper.sh: line 8: [hello: command not found
./mapper.sh: line 5: [world: command not found
./mapper.sh: line 8: [world: command not found
./mapper.sh: line 5: [instead: command not found
./mapper.sh: line 8: [instead: command not found
./mapper.sh: line 5: [it: command not found
./mapper.sh: line 8: [it: command not found
./mapper.sh: line 5: [will: command not found
./mapper.sh: line 8: [will: command not found
./mapper.sh: line 5: [give: command not found
./mapper.sh: line 8: [give: command not found
./mapper.sh: line 5: [word: command not found
./mapper.sh: line 8: [word: command not found
./mapper.sh: line 5: [counts.: command not found
./mapper.sh: line 8: [counts.: command not found
./mapper.sh: line 5: [lets: command not found
./mapper.sh: line 8: [lets: command not found
./mapper.sh: line 5: [see: command not found
./mapper.sh: line 8: [see: command not found
./mapper.sh: line 5: [map: command not found
./mapper.sh: line 8: [map: command not found
./mapper.sh: line 5: [reduce: command not found
./mapper.sh: line 8: [reduce: command not found
./mapper.sh: line 5: [in: command not found
./mapper.sh: line 8: [in: command not found
./mapper.sh: line 5: $'[action.\r': command not found
./mapper.sh: line 8: $'[action.\r': command not found

I have checked a lot of places for incorrect syntax however cannot narrow down as to what is going wrong.

Answer 1

To avoid spaces problems among "read line" use while in this way:

#!/bin/bash

FILE=$1
CNT=0
while read line; do
    if [[ $line == "hello world" ]]; then
        CNT=$(( $CNT + 1 ))
    fi  
done < $1

echo "File '$1' has $CNT times the 'hello world' phrase"

To run the script, pass your wordfile as a parameter, like that:
./mapper.sh mr_test.txt

Answer 2

[ is not part of the shell grammar, but is a command. The problem is more obvious is you spell it test . (The only difference between the command test and the command [ is that [ requires that its last argument be ] ).

if [ "$token" = "hello" ] is semantically the same as if test "$token" = hello . It should be obvious that if test"$token" = hello is an error, which ought to make it clear why if ["$token" = hello ] is an error.

Note that quoting rules are important, and perhaps it needs to be made explicit that if test"$token" is treated exactly the same as if "test$token" .

For this particular script, you're better off using a case statement:

while read line; do
  for token in $line; do
    case $token in
    hello) echo hello,1;;
    world) echo world,1;;
    esac
  done
done

Answer 3

This should work for you. Shell is touchy about spaces - especially around "[" which is not considered a square bracket but a condition check.

while read line;
do
        for token in $line
        do
                if [ $token = "hello" ]; then
                        echo "Hello,1"
                elif [ $token = "world" ]; then
                        echo "world,1"
                fi
        done
done