Print previous, current and next line using sed

Shell Programming and Scripting
1

Hi,
how can i print the previous, current and next line using sed?
current line is the matching line.

The following prints all lines containing 'Failure' and also the immediate next line
cat $file | sed -n -e '/Failure/{N;p;}'

Now, i also want to print the previous line too.

Thanks,
-srinivas yelamanchili

2 
sed -n -e '/Failure/{x;1!p;g;$!N;p;D;}' -e h  inputfilename
3

Thanks Jim, this worked.
-srinivas

4

Another option would be to use grep

grep -n -C1 Failure filename

-Prathap

5

If your grep version (GNU) supports the -A and -B option:

grep -A 1 -B 1 'Failure' file

Regards

6 
sed -n '/pattern/ !{
h
}
/pattern/ {
N
H
x
p
}' filename
7

Thanks to all for the solution.
-A, B, C options are not supported.
Using HP-UX 11.11

Now, can i print just the previous line and the matching line?
cat replace_all* | sed -n -e 'N;/Failure/p;'
prints the previous line only for the first match, thereafter only matching lines are printed and not their previous lines.

Thanks,
-srinivas

8

use awk its easy

awk 'c-->0;$0~s{if(b)for(c=b+1;c>1;c--)print r[(NR-c+1)%b];print;c=a}b{r[NR%b]=$0}' b=1 a=1 s="pattern" filename
9

Or:

awk '/Failure/{print s "\n" $0;getline;print;exit}{s=$0}' file

Regards