Remove certain characters in shell script

Question

I ran this command in shell script-

echo grep datadir /etc/my.cnf

this is the output i got-

datadir=/var/lib/mysql

What should I do to get the output as-

/var/lib/mysql

The output does not match the command you posted. Either the echo is wrong, or you have omitted a (useless) pair of backticks. — tripleee
– tripleee, Commented Dec 8, 2012 at 10:54

cnicutar · Accepted Answer · 2012-12-08 10:49:04Z

2

How about:

[cnicutar@fresh ~]$ echo $str
datadir=/var/lib/mysql
[cnicutar@fresh ~]$ echo ${str#*=}
/var/lib/mysql

Read more about these operations at the ABS.

answered Dec 8, 2012 at 10:49

cnicutar

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Comments

Scout · Accepted Answer · 2012-12-08 10:54:49Z

2

Pipe the output of the grep in a cut:

$ echo 'datadir=/var/lib/mysql' | cut -d '=' -f 2
/var/lib/mysql

You might run with problems if there are spaces in your file though (note the indent on the output):

$ echo 'datadir =  /var/lib/mysql' | cut -d '=' -f 2
  /var/lib/mysql

You could use awk to circumvent this:

$ echo 'datadir =  /var/lib/mysql' | awk -F '[[:space:]]*=[[:space:]]*' '{print $2}'
/var/lib/mysql

answered Dec 8, 2012 at 10:54

Scout

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Comments

Dan Graller · Accepted Answer · 2012-12-08 10:56:26Z

1

use cut with the -d option

grep datadir /etc/my.cnf | cut -d = -f 2

edited Dec 8, 2012 at 10:56

answered Dec 8, 2012 at 10:50

Dan Graller

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Emil Vikström · Accepted Answer · 2012-12-08 10:50:39Z

0

Pipe it through sed 's/^datadir=//' which means "replace the leading datadir= with nothing".

answered Dec 8, 2012 at 10:50

Emil Vikström

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1 Comment

tripleee Over a year ago

Or better yet only use sed -n 's/^datadir=//p' /etc/my.cnf without any grep or echo.

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