NEWBIE: grep using yesterdays date?

hristo77 · 11-05-2015, 06:12 AM

Hi,

Im trying to grep for yesterdays date like this

Code:

cat logfile_rman.log | grep '\-*' -A 5 | grep 'date +%Y%m%d -d yesterday' -A 500 | grep 'RMAN-' -C 1 | wc -l

Tried this as well:

exp_date=$(date +%Y%m%d -d yesterday)

cat logfile_rman.log | grep '\-*' -A 5 | grep '$exp_date' -A 500 | grep 'RMAN-' -C 1 | wc -l

The code works if I replace date with '20151104', I then get a wc of 20.

Whats wrong?

Regards
H

HMW · 11-05-2015, 06:42 AM

Quote:

Originally Posted by hristo77

Hi,

Im trying to grep for yesterdays date like this

Code:

cat logfile_rman.log | grep '\-*' -A 5 | grep 'date +%Y%m%d -d yesterday' -A 500 | grep 'RMAN-' -C 1 | wc -l

Tried this as well:

exp_date=$(date +%Y%m%d -d yesterday)

cat logfile_rman.log | grep '\-*' -A 5 | grep '$exp_date' -A 500 | grep 'RMAN-' -C 1 | wc -l

The code works if I replace date with '20151104', I then get a wc of 20.

Whats wrong?

Regards
H

Hi!

Get rid of the single quotes in your grep.

Like this:

Code:

echo "foo 20151104" | grep $exp_date 
foo 20151104

As you can see, this works as expected. But not:

Code:

$ echo "foo 20151104" | grep '$exp_date'

^This returns nothing.

Edit:
To add to the confusion, you can use double quotes:

Code:

echo "foo 20151104" | grep "$exp_date" 
foo 20151104

Bash can be very confusing at times!

Best regards,
HMW