Shell Programming and Scripting

Hello,

I am writing a shell script to do the following. It greps information from the messages log and then I use the cut command to isolate the field I need (the username) and output the information to a text file.

I now have to do the following. Count how many times each user logged in. So if the name "Mike" appears five times in the text file my script has to say Mike logged in five times.

It was suggested to me that I use awk to store the information from the text file in an array and process the information.

Though I am familiar with program design and concepts, I am rather new to shell scripting and awk and would ask the forum to provide me with some concrete code to help me understand what needs to be done.

IF the file (inputfile in example below) has the first field = username (first field = $1 in awk)

Code:

awk '{ arr[$1]++; continue }
       END { for (i in arr) {print i, arr[i] }'   inputfile

awk uses associative arrays, before you ask.

Hello,

I used the code you provided as follows. In my shell script I have a line that calls the awk script:

awk -f processing.awk names.tmp

In processing.awk I modified your code as follows:
{ arr[$1]++; continue }
END { for (i in arr) {print i, arr[i] }

When the script runs it says:
awk: processing.awk:3: { arr[$1]++; continue }
END { for (i in arr) {print i, arr[i] }

awk: processing.awk:3: ^ syntax error

Can you help me troubleshoot the problem please?