awk: print lines only when two lines with $NF == "string" found. 1

[w5000]

hello,

print no line if only one or more than two has been found.

$ echo "1 2 3 stringA\n3 4 5 stringA"|awk '$NF == "stringA"'
1 2 3 stringA
3 4 5 stringA

current workaround:
TEST_INPUT="1 2 3 stringA\n3 4 5 stringB"
if [ `echo ${TEST_INPUT}|awk '$NF == "stringA"'|wc -l` -eq 2 ]
then
echo ${TEST_INPUT}|awk '$NF == "stringA"'
fi

can it be done with the only 'awk' command in:

echo "1 2 3 stringA\n3 4 5 stringB"|[red]awk '$NF == "stringA"'[/red]

 

[feherke]

Hi

This is a typical case for double passing : first just count, when just output :

awk '[navy]FNR[/navy][teal]==[/teal]NR[teal]{[/teal][navy]$NF[/navy][teal]==[/teal][green][i]"stringA"[/i][/green][teal]&&[/teal]c[teal]++;[/teal][b]next[/b][teal]}[/teal][navy]c[/navy][teal]==[/teal][purple]2[/purple][teal]&&[/teal][navy]$NF[/navy][teal]==[/teal][green][i]"stringA"[/i][/green]' /input/file /input/file

In case your input will come from the standard input, will need the shell's process substitution feature :

awk '[navy]FNR[/navy][teal]==[/teal]NR[teal]{[/teal][navy]$NF[/navy][teal]==[/teal][green][i]"stringA"[/i][/green][teal]&&[/teal]c[teal]++;[/teal][b]next[/b][teal]}[/teal][navy]c[/navy][teal]==[/teal][purple]2[/purple][teal]&&[/teal][navy]$NF[/navy][teal]==[/teal][green][i]"stringA"[/i][/green]' <( echo "$TEST_INPUT" ) <( echo "$TEST_INPUT" )

In case the input is huge, is preferable to use optimized code, even if it is abit longer :

awk '[navy]FNR[/navy][teal]==[/teal]NR[teal]{[/teal][navy]$NF[/navy][teal]==[/teal][green][i]"stringA"[/i][/green][teal]&&[/teal]c[teal]++;[/teal][b]next[/b][teal]}[/teal][navy]FNR[/navy][teal]==[/teal][purple]1[/purple][teal]&&[/teal]c[teal]!=[/teal][purple]2[/purple][teal]{[/teal][b]exit[/b][teal]}[/teal][navy]$NF[/navy][teal]==[/teal][green][i]"stringA"[/i][/green]' /input/file /input/file

[gray]# or[/gray]

awk '[navy]FNR[/navy][teal]==[/teal]NR[teal]{[/teal][navy]$NF[/navy][teal]==[/teal][green][i]"stringA"[/i][/green][teal]&&[/teal]c[teal]++;[/teal][b]next[/b][teal]}[/teal][navy]FNR[/navy][teal]==[/teal][purple]1[/purple][teal]&&[/teal]c[teal]!=[/teal][purple]2[/purple][teal]{[/teal][b]exit[/b][teal]}[/teal][navy]$NF[/navy][teal]==[/teal][green][i]"stringA"[/i][/green]' <( echo "$TEST_INPUT" ) <( echo "$TEST_INPUT" )

Feherke.
[link feherke.github.com/]

http://feherke.github.com/

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