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Accepted
yael
Asked: 2012-04-19 23:35:24 +0800 CST

awk + perl + get two arguments in to awk syntax

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please advice what wrong with my awk syntax and how to fix it ( this syntax is in my ksh script ) and I run my script on linux machine

my target is to get from the file.txt only the lines that between the dates:

FROM 2012-04-19 TO 2012-04-22

remark - other solution can be with perl

[root@test1 /var/tmp]# a='2012/04/19'
[root@test1 /var/tmp]# b='2012/04/22'
[root@test1 /var/tmp]# awk -v A=$a -v B=$b '/A/,/B/' file.txt
awk: syntax error near line 1
awk: bailing out near line 1

file.txt 

[ 2012/04/18 21:49:01:857 ] Monitor::handle_client_message(): 
[ 2012/04/18 21:50:02:379 ] Monitor::handle_client_message(
[ 2012/04/18 21:57:52:64  ] Monitor::handle_client_message():
[ 2012/04/18 21:57:52:252 ] Monitor::handle_client_message(
[ 2012/04/18 21:58:46:958 ] Monitor::handle_client_message():

[ 2012/04/19 21:58:46:958 ] Monitor::handle_client_message(): 
[ 2012/04/20 21:58:46:958 ] Monitor::handle_client_message(): 
[ 2012/04/21 21:58:46:958 ] Monitor::handle_client_message(): 
[ 2012/04/22 21:58:46:958 ] Monitor::handle_client_message():
linux perl bash awk shell-scripting

2 Answers

  1. Best Answer

    You can use this command:

    $ awk '/2012\/04\/19/,/2012\/04\/22/' file.txt

    You need to escape the slashes as shown.

    Edit:

    It can be done using variables like:

    $ a='2012\/04\/19'
$ b='2012\/04\/22'
$ awk "/$a/,/$b/" file.txt
[ 2012/04/19 21:58:46:958 ] Monitor::handle_client_message(): 
[ 2012/04/20 21:58:46:958 ] Monitor::handle_client_message(): 
[ 2012/04/21 21:58:46:958 ] Monitor::handle_client_message(): 
[ 2012/04/22 21:58:46:958 ] Monitor::handle_client_message():

    Edit2:

    Escaping the slashes can be using done sed command like:

    $ a='2012/04/19'
$ aa=$(echo $a | sed 's/\//\\\//g')
$ echo $aa
2012\/04\/19

    Then, you can aa instead of a. Similarly, it can be done for b.

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  2. The following is the correct way to do what you want.

    You don't want to have to pre-escape your search patterns and you should use the -v option as you show in your question (but the shell variables should be quoted).

    When you have patterns in variables, you can't use // to surround the patterns - you have to use the match operator ~ (tilde).

    This works correctly for your data:

    a='2012/04/19'
b='2012/04/22'
awk -v A="$a" -v B="$b" '$0 ~ A, $0 ~ B' file.txt

    The reason you can't put variables inside // is that the characters in the name of the variable are seen as the pattern rather than the contents of the variable.

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