Display a block of text with AWK

awk '/start_pattern/,/stop_pattern/' file.txt
I find this terribly useful for grepping through a file, looking for just a block of text. There's "grep -A # pattern file.txt" to see a specific number of lines following your pattern, but what if you want to see the whole block? Say, the output of "dmidecode" (as root): dmidecode | awk '/Battery/,/^$/' Will show me everything following the battery block up to the next block of text. Again, I find this extremely useful when I want to see whole blocks of text based on a pattern, and I don't care to see the rest of the data in output. This could be used against the '/etc/securetty/user' file on Unix to find the block of a specific user. It could be used against VirtualHosts or Directories on Apache to find specific definitions. The scenarios go on for any text formatted in a block fashion. Very handy.

85
By: atoponce
2009-03-28 14:28:59
awk

3 Alternatives + Submit Alt

What Others Think

Very nice. dmidecode | awk '/Core/,/^$/'
Williebee · 503 weeks and 2 days ago
Awesome! Awk is such a powerful tool and I always wish I knew it better.
philiph · 503 weeks and 2 days ago
Thanks a lot
megerdin · 503 weeks and 2 days ago
Nice! I like using this for xml files.
tajohnson · 497 weeks and 3 days ago
because your '^$' is included in the pattern it'll also be output. You can prevent the empty line being output with the following: awk '/foo/,/^$/{if ($0 > 0) print}' Also, if the data is structured in a consistant way you can set RS to the particular record, ie: awk '{RS="Cell"}/MY_AP/' which will output the particular record for the ESSID "MY_AP".
khayyam · 295 weeks and 3 days ago
hmmmm ... the last command was chomped, I assume as I used a subshell ... anyhow it should read (without subshell): iwlist wlan0 scan |awk '{RS="Cell"}/MY_AP/'
khayyam · 295 weeks and 3 days ago
Does not work
iamvivek · 190 weeks and 5 days ago

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