awk with (if condition)

UNIX for Beginners Q & A
1

I'm unable to apply if condition to extract tsalary < 7000 and also want to sort data without disturbing header
some commands which i used here are:-

awk '{if(tsalary($4) < 7000)}' employee
tail -5 employee|awk '{print $4}' employee
tail -5 |sort -r employee

Name	tDesignation	tDepartment	tSalary
Thomas	Manager		Sales		        5000
Jason	Developer	       Technology	        5500
Sanjay	Sysadmin	       Technology	        7000
Nisha	Manager	        Marketing      	9500
Vicky	DBA		       Technology	         6000
2

Something like this?

[~/tmp] 0 $ awk  '$4 <= 7000 {print}' "file.txt" | grep -v tSalary  | sort -k 4

Thomas	Manager		Sales		5000
Jason	Developer	Technology	5500
Vicky	DBA		Technology	6000
Sanjay	Sysadmin	Technology	7000

Hope this helps

EDIT:
Had < > the wrong way

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3

yes! this command is very useful but in some cases it also give header along with the extracted data
awk '$5 >= 6000' "employee" | grep -v tsalary | sort -k 5

500 Vicky DBA Technology 6000
300 Sanjay Sysadmin Technology 7000
400 Nisha Manager Marketing 9500
id Name tDesignation tDepartment tSalary

4

Dont do BOLD for code.
Do

CODE

for code.

And proper writing helps.... tSalary....
Or use grep -i ...

And btw...
Your code would not show the 'header' on occasion, but always...
Unless your headings differ from file to file...

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5

Try this for leading header and sorted data:

awk 'NR == 1; $4 < 7000 {print | "sort -k4"}' file
Name	tDesignation	tDepartment	tSalary
Thomas	Manager	Sales	5000
Jason	Developer	Technology	5500
Vicky	DBA	Technology	6000
6

I slightly modified your code...
Was not my first attempt, just one of the... lets do this variant with the current variable... moments...

I have no idea WHY this works, because I wanted to EXclude the 'Name'-line with != and =! just to be sure:

awk '$1 == Name; $4 < 7000 {print | "sort -k4"}' file.txt
Thomas	Manager		Sales		5000
Jason	Developer	Technology	5500
Vicky	DBA		Technology	6000

EDIT:
Figured:

awk '$1 ==! "Name"; $4 < 7000 {print | "sort -k4"}' file.txt
Thomas	Manager		Sales		5000
Jason	Developer	Technology	5500
Vicky	DBA		Technology	6000

But I still dont understand why $1 == Name removes the Name/tSalary-line

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7

Try this:

awk '$1 == "Name"; $4 < 7000 {print | "sort -k4"}' file
Name    tDesignation    tDepartment    tSalary
Thomas    Manager    Sales    5000
Jason    Developer    Technology    5500
Vicky    DBA    Technology    6000

Name unquoted is an uninitialized variable name defaulting to "". Any empty $1 in sight?

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8

And that is why I dont understand why $1 == Name removes the "Name" line and shows the remaining values...
Because $1 is not empty -> it contains 'Name'... (and then the names...)

Cant wrap my head around that.
(can you 'follow' my confusion?)

And the TO did/does not want the header-line shown, that is why I settled for $1 ==! "Name"

9

It doesn't. It would remove any line with an emtpy $1, of which there is none. You can leave it out entirely. The $4 < 7000 removes the header line. $4 > 7000 would not; we'd need a different criterion, then.

Hmm - that ==! is a construct that I can't get my head around. It obviously is a correct syntax - no complaints by the interpreter. So the == must be separated from the ! which then logically negates the NAME variable's contents and results in a 1 or 0 which in turn is tried to be matched against $1 . And, so it is. Add a line starting with a 0 or 1 and see what's going to happen.

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