Awk, Shell Scripting

Question

I have a file which has the following form:

#id|firstName|lastName|gender|birthday|creationDate|locationIP|browserUsed
111|Arkas|Sarkas|male|1995-09-11|2010-03-17T13:32:10.447+0000|192.248.2.123|Midori

Every field is separated with "|". I am writing a shell script and my goal is to remove the "-" from the fifth field (birthday), in order to make comparisons as if they were numbers.

For example i want the fifth field to be like |19950911|

The only solution I have reached so far, deletes all the "-" from each line which is not what I want using sed.

i would be extremely grateful if you show me a solution to my problem using awk.

You do not need to remove the -s since a string comparison of YYYY-MM-DD will produce the same relative order as a numeric comparison of YYYYMMDD. — Ed Morton
– Ed Morton, Commented Mar 20, 2016 at 20:47

karakfa · Accepted Answer · 2016-03-20 17:38:00Z

3

If this is a homework writing the complete script will be a disservice. Some hints: the function you should be using is gsub in awk. The fifth field is $5 and you can set the field separator by -F'|' or in BEGIN block as FS="|"

Also, line numbers are in NR variable, to skip first line for example, you can add a condition NR>1

edited Mar 20, 2016 at 17:38

answered Mar 20, 2016 at 17:30

karakfa

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1 Comment

Aris Kantas Over a year ago

My problem is that I speek Greek and I can't find proper gsub documentation that i can understand. The homework task is only this so it is a "one-line" solution that's why I did not write the full script.

Arif Burhan · Accepted Answer · 2016-03-20 18:08:24Z

1

An awk one liner:

awk 'BEGIN { FS="|" } { gsub("-","",$5); print }' infile.txt

answered Mar 20, 2016 at 18:08

Arif Burhan

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4 Comments

Aris Kantas Over a year ago

Yes that finally worked. But I want to ask one more thing. At the command you wrote if i write: awk 'BEGIN { FS="|" } { gsub("-","",$5); print $1,"|",$2 }' infile.txt The result is "Whatever $1 is" "blank" "|" "blank" "Whatever $2 is". How do i remove blank spaces?

jas Over a year ago

Remove the commas: print $1 "|" $2. OR you can set OFS: BEGIN {OFS=FS="|"} {gsub...; print $1, $2}. Note that when you set OFS (output file separator) you keep the commas, but don't explicitly print the |.

Aris Kantas Over a year ago

That was very helpful. I appreciate it.

Ali ISSA Over a year ago

You can define OFS value as "|"

Ali ISSA · Accepted Answer · 2016-03-20 21:54:07Z

1

To keep "|" as output separator, it is better to define OFS value as "|" :

... | awk 'BEGIN { FS="|"; OFS="|"} {gsub("-","",$5); print $0 }'

answered Mar 20, 2016 at 21:54

Ali ISSA

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