AWK number range

[Patrick Ware_1]

Hello all. I am in the process of doing mass edits on a file that deals with security defaults. I am using an awk line to check for PASSLENGTH being 8 or more in the file. If it is less than 8, I want to replace the line with:

PASSLENGTH=8

Currently I am accomplishing this with the following below:

awk '{sub(/PASSLENGTH=6|PASSLENGTH=5|PASSLENGTH=4/,"PASSLENGTH=8")};{print}' ${CHG_FILE} > ${CHG_FILE}.tmp
mv ${CHG_FILE}.tmp ${CHG_FILE}

What I need to know is if there is a way to specify a range, or tell it instead that if the value for PASSLENGTH is 0=7, then take action?

Don't worry, when I pick up the kids today, I will be at the book store getting an awk reference book.

[Dennis Handly]

Something like:
awk '
{
sub(/PASSLENGTH=[0-7][^0-9]/,"PASSLENGTH=8")
print}'

If it is a two digit number, it will fail if you have 07.

[Patrick Ware_1]

0=7 should read as 0-7 in my first post.

[Hein van den Heuvel · Accepted solution]

How firm/predictable is the input ?

Any optional spaces or line comments to deal with?

You could tell awk to
- first look for lines starting with PASSLENGTH
- split into an array of words around =
- compare the second word with 8
- force fresh $0 line if less than 8
- print $0

$ awk '/^PASSLENGTH=/{ split ($0,a,/=/); if (a[2] < 8) $0 = a[1] "=8"} {print}' tmp.txt

example input/output below.

Hein

$ cat tmp.txt
PASSLENGTH=12
PASSLENGTH=18
PASSLENGTH=06
PASSLENGTH=6
xxxxxENGTH=6
PASSLENGTH=08
PASSLENGTH=0
PASSLENGTH=2
PASSLENGTH=10

---- output ----

PASSLENGTH=12
PASSLENGTH=18
PASSLENGTH=8
PASSLENGTH=8
xxxxxENGTH=6
PASSLENGTH=08
PASSLENGTH=8
PASSLENGTH=8
PASSLENGTH=10

[Patrick Ware_1]

Dennis, for some reason the help you gave me didn't seem to work out for me.

[Dennis Handly]

>for some reason the help you gave me didn't seem to work out for me.

Possibly you only had one digit, this works a little better:
sub(/PASSLENGTH=[0-7]$/,"PASSLENGTH=8")

But as with Hein's example, it is better to get that number than try to pattern match the possibly two digits.

[Patrick Ware_1]

Yes, it was only single digit numbers.