grep vs awk - Part 2

In this article, we will see more awk alternatives for the frequently used grep commands. This is in continuation to the grep vs awk - Part 1. Let us consider a sample file as shown below:

$ cat file
Unix

Linux
Uniix
Solaris
AIX
ArchLinux
Ubuntu

1. Search for a pattern present in a variable

$ x="Linux"
$ grep "$x" file
Linux

The variable x contains the search pattern. Using grep, the variable can directly be used.

$ awk -v var="$x" '$0 ~ var' file
Linux

In awk, the variable cannot be used directly. It needs to be passed to awk from shell using the -v option. More about the variable passing to awk.

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How to use arrays in ksh?

  Array, as in any programming language, is a collection of elements. These elements need not be of the same type. One important difference here is shells support only one-dimensional arrays.

1. Creating an array:
   Creating an array is pretty simple.

$ typeset -a arr
$ arr[0]=25
$ arr[1]=18
$ arr[2]="hello"

 Using the typeset command, we let the shell know that we are intending to use the variable arr to store a list of elements. The -a indicates arr as an indexed array. Then the elements are assigned one by one using their index positions. Array indexing always starts from 0.

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