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Grep to remove and add specified characters

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# 1  
Old 05-16-2014
Grep to remove and add specified characters
I have the following type of 2 column file:

Code:
motility	-
role	-
supplementation	-
age	b
ancestry	b
purity	b
recommendation	b
serenity	b
unease	b
carving	f
expansion	f

I would like to print only certain sections of the file depending on the value of the second column.

For instance, I only want to print those lines that have "-" as the value of the second column.

However, in the output, I also want to add the following characters to each line end, for a desired result of:

Code:
motility-n
role-n
supplementation-n

Is there a
Code:
grep

that allows me to do this?
Can anyone help me with this issue?
# 2  
Old 05-16-2014
try
Code:
awk '/-/ {print $0"n"}' filename

OR
Code:
awk '{gsub (/^ */,"",$1); print}' file| awk '/-/ {print $0"n"}'

output
Code:
motility -n
role -n
supplementation -n

Last edited by Makarand Dodmis; 05-16-2014 at 05:58 AM..
# 3  
Old 05-16-2014
Try also
Code:
awk '$2==SRCH {print $1 SRCH "n"}' SRCH="-" file
motility-n
role-n
supplementation-n

# 4  
Old 05-16-2014
No. The grep utility searches for lines matching a regular expression, it does not change/replace text on matched lines.
Try:
Code:
sed -n 's/      -$/-n/p' filename

If it isn't obvious, the 1st part of the sed substitute command contains a literal tab character, not spaces (<s></><tab><minus-sign><dollar-sign></>...).

Or to make Makarand Dodmis' awk script work, you could try:
Code:
awk -F '\t' '$2 == "-" {print $1"-n"}' filename

Note that if you try this on a Solaris/SunOS system, change awk to /usr/xpg4/bin/awk, /usr/xpg6/bin/awk, or nawk.
This User Gave Thanks to Don Cragun For This Post:
Makarand Dodmis
# 5  
Old 05-16-2014
how about
Code:
awk '/-/ {print $1"-n"}' file

# 6  
Old 05-16-2014
That would still be vulnerable to "-" anywhere on the line.
This User Gave Thanks to RudiC For This Post:
Makarand Dodmis
# 7  
Old 05-16-2014
right
Code:
awk '$2 ~ /-/ {print $1"-n"}' file

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