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sed pattern substitution issue?

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# 1  
Old 03-16-2011
sed pattern substitution issue?
Hello everyone ...
I'm going crazy, I hope some of you can help me ...

I have to replace a line in a crontab like this:

Code:
5 2 * * 2 root backupdat

with this:

Code:
5 5 * * 3 root backupdat


the command I use is the following:


Code:
sed -i.bak -e 's/5 2 * * 2 root backupdat/5 5 * * 3 root backupdat/' /etc/crontab

why can not replace that line?
something wrong?

thanks a lot
# 2  
Old 03-16-2011
Try this:
Code:
's/5 2 \* \* 2 root backupdat/5 5 * * 3 root backupdat/' /etc/crontab

This User Gave Thanks to tene For This Post:
ionral
# 3  
Old 03-16-2011
Quote:
Originally Posted by tene
Try this:
Code:
's/5 2 \* \* 2 root backupdat/5 5 * * 3 root backupdat/' /etc/crontab

excellent!
just not enough, let me explain better ...
I want to replace the line coming out from a grep, so I can not insert \ before *
how can I solve this problem?

thanks again
# 4  
Old 03-16-2011
This command will give you escaped * from your grep command. Then use it in the final sed command.
Code:
grep <pattern> <file> | sed 's/*/\\*/g'

This User Gave Thanks to tene For This Post:
ionral
# 5  
Old 03-16-2011
Quote:
Originally Posted by tene
This command will give you escaped * from your grep command. Then use it in the final sed command.
Code:
grep <pattern> <file> | sed 's/*/\\*/g'

it is true .. I had not thought of that!
Thank you very much and sorry for my ignorance ...Smilie
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