CODEWITHSUNDEEP
regexbashsedsolaris
JavaRed
JavaRed

Reputation: 708

Regular expression in sed

I try to use regex in a sed command. I try to replace a pattern. My pattern is a line in /etc/security/policy.conf file. The value is unknown it should be either:

#LOCK_AFTER_RETRIES=NO or LOCK_AFTER_RETRIES=4 (or any number here). I want to replace found pattern with the value LOCK_AFTER_RETRIES=6. So I tried the command:

sed 's/#*LOCK_AFTER_RETRIES=[a-zA-Z0-9][a-zA-Z0-9]/LOCK_AFTER_RETRIES=6/g' ./policy.conf

But it didn't look to be working.

Thanks.

Upvotes: 1

Views: 379

Answers (3)

qqibrow
qqibrow

Reputation: 3022

Is this what you want?

sed -i 's/LOCK_AFTER_RETRIES=.*/LOCK_AFTER_RETRIES=6/g' filename

I test like this and it works:

echo "LOCK_AFTER_RETRIES=4\n#LOCK_AFTER_RETRIES=NO" | sed 's/LOCK_AFTER_RETRIES=.*/LOCK_AFTER_RETRIES=6/g'

[EDIT]

After checking other's answer, I am not sure whether you want to replace #LOCK_AFTER_RETRIES=NO to LOCK_AFTER_RETRIES=6 or #LOCK_AFTER_RETRIES=6.

My above answer will change #LOCK_AFTER_RETRIES=NO to #LOCK_AFTER_RETRIES=6

If you want to change change #LOCK_AFTER_RETRIES=NO to LOCK_AFTER_RETRIES=6, try: sed -i 's/^#*LOCK_AFTER_RETRIES=.*/LOCK_AFTER_RETRIES=6/g' filename

In summary:

echo "LOCK_AFTER_RETRIES=4\n#LOCK_AFTER_RETRIES=NO" | sed 's/LOCK_AFTER_RETRIES=.*/LOCK_AFTER_RETRIES=6/g'
LOCK_AFTER_RETRIES=6
#LOCK_AFTER_RETRIES=6
echo "LOCK_AFTER_RETRIES=4\n#LOCK_AFTER_RETRIES=NO" | sed 's/^#*LOCK_AFTER_RETRIES=.*/LOCK_AFTER_RETRIES=6/g'
LOCK_AFTER_RETRIES=6
LOCK_AFTER_RETRIES=6

Upvotes: 1

Amit
Amit

Reputation: 20456

Try this:

sed '/LOCK_AFTER_RETRIES/s/=.*/=6/g'  ./policy.conf

Upvotes: 0

Kent
Kent

Reputation: 195079

give this a try:

sed 's/^#\?\s*LOCK_AFTER_RETRIES=[^=]*/LOCK_AFTER_RETRIES=6/'

test with some example:

# LOCK_AFTER_RETRIES=NO
#LOCK_AFTER_RETRIES=NO
 LOCK_AFTER_RETRIES=4
LOCK_AFTER_RETRIES=4

kent$  sed 's/^#\?\s*LOCK_AFTER_RETRIES=[^=]*/LOCK_AFTER_RETRIES=6/' f
LOCK_AFTER_RETRIES=6
LOCK_AFTER_RETRIES=6
LOCK_AFTER_RETRIES=6
LOCK_AFTER_RETRIES=6

Upvotes: 2

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