Syntax error in bash

Question

I want to write script in bash (I start programming in bash), but i have error, i try everything, and still i don't know how to repair this.

#!/bin/bash
cap=0
cat|while read line
  do
  read a
    if[$a -gt $cap]
       then echo "MORE"
fi
done

That's easy script, but i'm newbie in bash, please someone help me ;)

First off, $line already contains the current line that was read from the input file, so you don't need the second read a or else you're going to miss half the lines of the input file. — Burton Samograd
– Burton Samograd, Commented May 1, 2012 at 17:16
Second you don't need the cat|, the while read will read from stdin without that. — Burton Samograd
– Burton Samograd, Commented May 1, 2012 at 17:16

Charles Duffy · Accepted Answer · 2012-05-01 17:16:48Z

8

The syntax error is here:

if[$a -gt $cap]

You need whitespace, and quotes (to be safe with content with spaces or empty values):

if [ "$a" -gt "$cap" ]

Somewhat better would be to use the [[ test mechanism, which is syntax (rather than [, which is a command), and doesn't need double quotes to be safe:

if [[ $a -gt $cap ]]

Even better than that would to be use a math context, which lets you use traditional mathematical operators and automatically dereferences variables:

if (( a > cap )) ; then ...
fi

answered May 1, 2012 at 17:16

Charles Duffy

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