I have a .gz file with contents like the following:
ID:123455 23-07-2015 mvni
warning: RTM post
warning : no profile data
Using the string no profile data, I want to print the ID.
I tried with grep before and after lines but it's not working. Please suggest any other methods.
$ zgrep -B2 'warning : no profile data' *.gz | grep -o '^ID:[0-9]*'
ID:123455
As pointed out by user3188445, zgrep will grep for strings within (possibly compressed) files. Using -B2 to print 2 lines before the warning match, then extracting the IDs of all matching files using a standard grep against stdout.
This will work whether you have several compressed files, or several matching sections within the same file.
zgrep as well.
zgrep -l 'warning : no profile data' *.gz | xargs zgrep '^ID:' | sed -e 's/^ID:\([0-9]*\) .*/\1/', as suggested by user3188445. That will work with your version of zgrep.
The zcat command or gzip -dc will uncompress and print the output of a gzipped file to stdout. So you can run, for example, zcat file.gz | grep '^ID:'. However, most systems have a command called zgrep that already does that for you.
Under the assumption that you have a bunch of these files, and want to print the ID line from files that contain a particular warning, you can do this:
zgrep -l 'warning : no profile data' *.gz | xargs zgrep '^ID:'
The first command, zgrep -l, prints a list of files that contain the warning. The second command, xargs, takes a list of arguments on standard input and runs a command on all the inputs. The command it runs is also zgrep, so as to print the ID line you want.
To extract just the numeric ID, take the command I previously suggested and append
| sed -e 's/^ID:\([0-9]*\) .*/\1/'
That will just print the ID number.
You can use zgrep to grep a .gz file. I suspect you want something like:
zgrep -B 2 'warning : no profile data' file.gz
zcat file.gz | grep -B 2 'warning : no profile data'
If you have access to GNU utilities, this should work:
zgrep -B2 "no profile data" file | grep -oP 'ID:\K\d+'
If that doesn't work, you can try this instead:
zcat file.gz | grep -B2 "no profile data" | sed -n 's/ID:\([0-9]*\).*/\1/p'
Or:
zcat file.gz |
awk '{if(/^ID/){split($1,a,/:/); id=a[2];}if(/no profile data/){print id}}'
Or:
zcat file.gz | perl -lne '$id=$1 if /^ID:(\d+)/; print $id if /no profile data/'