Tuesday, 19 August 2008

awk: finding the last occurence of a string

OK, these awk commands use the same theory as when I introduced arrays. Here are some examples for finding the last occurrence of a string:

Finding the last occurance of a string:

awk -F, '/SMPP Enquire Link timeout/ { lines[last] = $0 } END { print lines[last] }' 070403.OLG

awk -F, '/No linkset found for rk_pc/ { lines[last] = $0 } END { print lines[last] }' messages

awk -F, '/Verification Tag mismatch... packet dropped/ { lines[last] = $0 } END { print lines[last] }' messages

The above was based on this which gets the last distinct line based on field $2 (which we're using as our array index - the value of the array component is set to $0):

lines[$2] = $0
for (i in lines)
print lines[i]

This awk script gets distinct lines from a file based on field $2.

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