How to fix the error in the bash shell script?

Question

I am trying a code in shell script. while I am trying to convert the code from batch script to shell script I am getting an error.

BATCH FILE CODE

:: Create a file with all latest snapshots
FOR /F "tokens=5" %%a in (' ec2-describe-snapshots ^|find "SNAPSHOT" ^|sort /+64') do set "var=%%a" 
set "latestdate=%var:~0,10%" 
call ec2-describe-snapshots |find "SNAPSHOT"|sort /+64 |find "%latestdate%">"%EC2_HOME%\Working\SnapshotsLatest_%date-today%.txt"

CODE IN SHELL SCRIPT

#Create a file with all latest snapshots
FOR snapshot_date in $(' ec2-describe-snapshots | grep -i "SNAPSHOT" |sort /+64') do set "var=$snapshot_date" 
set "latestdate=$var:~0,10" 
ec2-describe-snapshots |grep -i "SNAPSHOT" |sort /+64 | grep "$latestdate">"$EC2_HOME%/SnapshotsLatest_$today_date"

I want to sort the snapshots according to dates and to save the snapshots that are created in latest date in a file.

SAMPLE OUTPUT OF ece-describe-snapshots:

SNAPSHOT snap-5e20 vol-f660 completed 2013-12-10T08:00:30+0000 100% 109030037527 10 2013-12-10: Daily Backup for i-2111 (VolID:vol-f9a0 InstID:i-2601)

It will contain records like this

I got this code :

latestdate=$(ec2-describe-snapshots | grep ^SNAPSHOT | sort -k 5 | awk '{print $5}') ec2-describe-snapshots | grep SNAPSHOT.*$latestdate | > "$EC2_HOME/SnapshotsLatest_$today_date"

but getting this error :

grep: 2013-12-10T09:55:34+0000: No such file or directory grep: 2013-12-11T04:16:49+0000: No such file or directory grep: 2013-12-11T04:17:57+0000: No such file or directory

i have some snapshots made on amazon, i want to find the latest snapshots made on a date and then want to store them in a file. like date 2013-12-10 snapshots made on this date should be stored in file. Contents of snapshotslatest file should be

SNAPSHOT snap-c17f3 vol-f69a0 completed 2013-12-04T09:24:50+0000 100% 109030037‌​527 10 2013-12-04: Daily Backup for Sanjay_Test_Machine (VolID:vol-f66409a0 InstID:i-26048111) SNAPSHOT snap-c7d617f9 vol-3d335f6b completed 2013-12-04T09:24:54+0000 100% 1090‌​30037527 10 2013-12-04: Daily Backup for sacht_VPC (VolID:vol-3db InstID:i-ed6)

please not that if there are snapshots created on 2013-12-10, 2013-12-11, 2013-12-12. It means that the latest_date should be 2013-12-12 and all the snaphshot created on 2013-12-12 should be saved in file.

Any suggestion or lead is appreciated.

Answer 1

Neither the batch script nor the shell script you posted are a good starting point so let's start from scratch. Sorry, this is too big for a comment.

You want to find the latest snapshots made on a date and then want to store them in a file.

What does that mean?

Do the snapshot files have a timestamp in their name or in their content?

If not - UNIX does not store file creation timestamps so is a last-modified timestamp adequate?

Do you literally want to concatenate all of your snapshot files into one singe file or do you want to create a file that has a list of the snapshot file names?

Post some sample input (e.g. some snapshot file names and contents if that's where the timestamp is stored) and the expected output given that input.

Update your question to address all of the above, do not try to reply in a comment.

Answer 2

Minor issue, you don't need a pipe when re-directing output, so your line to save should be

ec2-describe-snapshots | grep SNAPSHOT.*$latestdate  > "$EC2_HOME/SnapshotsLatest_$today_date"

Now the main issue here, is that the grep is messed up. I haven't worked with amazon snapshots, but judging by your example descriptions, you should be doing something like

latestdate=$(ec2-describe-snapshots | grep -oP "\d+-\d+-\d+" | sort -r | head -1)

This will get all the dates containing the form ffffdd-dd-dd from the file (I'm assuming the two dates in each snapshot line always match up), sort them in reverse order (latest first) and take the head which is the latest date, storing it in $latestdate.

Then to store all snapshots with the given date do something like

ec2-describe-snapshots | grep -oP "SNAPSHOT(.*?)$lastdateT(.*?)\)" > "$EC2_HOME/SnapshotsLatest_$today_date"

This will get all text starting with SNAPSHOT, containing the given date, and ending in a closing ")" and save it. Note, you may have to mess around with it a bit, if ")" can be present elsewhere.