Print the previous line

Shell Programming and Scripting
1

My requirement is that when ever search criteria matchs in log file, the previous line just above the search word as well as search word should be print.

sample log file

--03-19T11:26  xxx    create version "a.sh@@/main/6"
  "104157 "
--03-18T16:01  xxx    create version "a.sh@@/main/5"
  "104157 "
--03-16T12:51  xxx    create version "a.sh@@/main/4"
  "874569"
--03-09T17:49  xxx    create version "a.sh@@/main/3"
  "874569"
--02-23T07:21  xxx  create version b.sh@@/main/14
  "94145"
--02-22T07:12  xxx  create version "b.sh@@/main/13"
  "94145"
--02-21T00:10  xxx    create version "b.sh@@/main/12"
  "2010"
```[/i]


No if i search for 94145, then output shoul be \-
 
```text
--02-23T07:21  xxx  create version b.sh@@/main/14    <-- previous line   
  "94145"                                                              <-- search critria
--02-22T07:12  xxx  create version b.sh@@/main/13   <-- previous line   
  "94145"                                                  <-- search critria

another example, if user search for 2010, then output should be -[/i]

--02-21T00:10  xxx    create version "b.sh@@/main/12"
  "2010"

Any kind of help will be appriciated.

Thanks in advance.

2 
awk '$0 ~ v { print p RS $0 }
{ p = $0 }' v=94145 infile

And of course, you may need to make the search more specific.

3

Thanks!!

Can you please tell me should i use your suggestion as a awk script or as a command ??

---------- Post updated at 06:20 PM ---------- Previous update was at 06:19 PM ----------

Can yopu please ellobrate it more??

4

Hi, Try this

grep -B1 "94145" testfile
5

Consider that -A/B are supported only by GNU grep.

---------- Post updated at 02:57 PM ---------- Previous update was at 02:56 PM ----------

Just run the script on the command line:

awk '$0 ~ v { print p RS $0 } { p = $0 }' v=94145 <your_log_file_name>
6

I tried what you said and got following error message

 
$ awk '$0 ~ v { print p RS $0 } { p = $0 }' v=94145 log
awk: syntax error near line 1
awk: bailing out near line 1
$

Please remember that i am using K shell and Sun Solaries as OS

7

OK, just use nawk instead of awk.