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Full Discussion: Use the -B option with grep
Top Forums UNIX for Dummies Questions & Answers Use the -B option with grep Post 302789301 by Corona688 on Wednesday 3rd of April 2013 12:25:08 PM
Old 04-03-2013
In what way is that 'not working'? Does it not have that option, or does it accept it yet misbehave somehow?

For systems which don't have -B, you can write a small awk script:

Code:
$ cat context.awk

# Recall N lines ago up to 9 lines
function last(N)
{
        if(N>L) return("");
        return(LINE[(L-N)%10]);
}

{ LINE[(++L)%10]=$0 } # Remember line for later

$0 ~ REGEX  {   for(N=2; N>=0; N--) print last(N);      }

$ awk -f context.awk REGEX="FAILED" inputfile

Use nawk on solaris.
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ucblinks(1B)					     SunOS/BSD Compatibility Package Commands					      ucblinks(1B)

NAME
ucblinks - adds /dev entries to give SunOS 4.x compatible names to SunOS 5.x devices SYNOPSIS
/usr/ucb/ucblinks [-e rulebase] [-r rootdir] DESCRIPTION
ucblinks creates symbolic links under the /dev directory for devices whose SunOS 5.x names differ from their SunOS 4.x names. Where possi- ble, these symbolic links point to the device's SunOS 5.x name rather than to the actual /devices entry. ucblinks does not remove unneeded compatibility links; these must be removed by hand. ucblinks should be called each time the system is reconfiguration-booted, after any new SunOS 5.x links that are needed have been created, since the reconfiguration may have resulted in more compatibility names being needed. In releases prior to SunOS 5.4, ucblinks used a nawk rule-base to construct the SunOS 4.x compatible names. ucblinks no longer uses nawk for the default operation, although nawk rule-bases can still be specifed with the -e option. The nawk rule-base equivalent to the SunOS 5.4 default operation can be found in /usr/ucblib/ucblinks.awk. OPTIONS
-e rulebase Specify rulebase as the file containing nawk(1) pattern-action statements. -r rootdir Specify rootdir as the directory under which dev and devices will be found, rather than the standard root directory /. FILES
/usr/ucblib/ucblinks.awk sample rule-base for compatibility links ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWscpu | +-----------------------------+-----------------------------+ SEE ALSO
devlinks(1M), disks(1M), ports(1M), tapes(1M), attributes(5) SunOS 5.10 13 Apr 1994 ucblinks(1B)
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