Question

I have a log file which has call stacks logged within.

e.g

Call stack: [thread 0xb0468000]: | thread_start | _pthread_start | __NSThread__main__ | -[NSThread main] | -[AggregatorObjCWorkQueue newThreadMainLoop] | -[NSRunLoop(NSRunLoop) runMode:beforeDate:] | CFRunLoopRunInMode | CFRunLoopRunSpecific | __CFRunLoopRun | __CFRunLoopDoSources0 | __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ | __NSThreadPerformPerform | -[NSObject performSelector:withObject:] | -[AggregatorTask run] | -[ComAppAggregatorApiSystemClientWorkerFactory_$4_$1 run] | -[ComAppAggregatorFrameworkClientSubscriptionSyncer startWithComAppAggregatorApiClient:] | -[ComAppAggregatorSyncClientSyncSubscriptionRegistry addSubscriptionWithComAppAggregatorQueryQueryXML_Subscription:] | -[ComAppAggregatorSyncClientSyncSubscriptionRegistry newSyncAndPostWithComAppAggregatorQueryQueryXML_QueryKey:] | -[ComAppAggregatorSyncClientSyncSubscriptionRegistry writeUpdateWithComAppAggregatorQueryQueryXML_QueryKey:] | -[ComAppAggregatorSyncClientSyncSubscriptionRegistry writeSubscriptions] | -[JavaUtilTreeMap putWithId:withId:] TreeMap.m:371 | -[JavaUtilTreeMap createNodeWithId:withId:] TreeMap.m:634 | -[JavaUtilTreeMap_Node init] TreeMap.m:1463 | -[IOSObjectArray initWithLength:type:] IOSObjectArray.m:42 | calloc | malloc_zone_calloc

The objective is to create a file with unique call stacks, i.e copy the first occurence of this stack to another file and ignore all the others.

Similarly for call stacks of a different nature.

The constraint is that I need to use shell script to get this done.
Any pointers?

Answer 1

Just use the -u option (unique) of sort:

sort -u logfile.log