search for a string and return previous relating string if found

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

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Re: search for a string and return previous relating string if found by tybalt89 (Monsignor) on Dec 06, 2017 at 19:56 UTC
#!/usr/bin/perl use strict; use warnings; $/ = "!\n"; while( <DATA> ) { /^interface (.\n)(?: .\n)*? spanning-tree guard root/ and print $1 +; } __DATA__ ! interface other-one switchport access vlan 300 switchport mode access switchport port-security maximum 130 switchport port-security switchport port-security aging time 2 switchport port-security aging type inactivity no logging event link-status speed 100 duplex full srr-queue bandwidth share 1 60 30 10 srr-queue bandwidth shape 3 0 0 0 mls qos trust device cisco-phone storm-control broadcast level pps 1k storm-control multicast level pps 2k storm-control action shutdown storm-control action trap spanning-tree portfast spanning-tree bpduguard enable ! ! interface FastEthernet1/0/3 switchport access vlan 300 switchport mode access switchport port-security maximum 130 switchport port-security switchport port-security aging time 2 switchport port-security aging type inactivity no logging event link-status speed 100 duplex full srr-queue bandwidth share 1 60 30 10 srr-queue bandwidth shape 3 0 0 0 mls qos trust device cisco-phone storm-control broadcast level pps 1k storm-control multicast level pps 2k storm-control action shutdown storm-control action trap spanning-tree portfast spanning-tree bpduguard enable spanning-tree guard root ! ! interface other-two switchport access vlan 300 switchport mode access switchport port-security maximum 130 switchport port-security switchport port-security aging time 2 switchport port-security aging type inactivity no logging event link-status speed 100 duplex full srr-queue bandwidth share 1 60 30 10 srr-queue bandwidth shape 3 0 0 0 mls qos trust device cisco-phone storm-control broadcast level pps 1k storm-control multicast level pps 2k storm-control action shutdown storm-control action trap spanning-tree portfast spanning-tree bpduguard enable ! ! interface FastEthernet1/0/4 switchport access vlan 300 switchport mode access switchport port-security maximum 130 switchport port-security switchport port-security aging time 2 switchport port-security aging type inactivity no logging event link-status speed 100 duplex full srr-queue bandwidth share 1 60 30 10 srr-queue bandwidth shape 3 0 0 0 mls qos trust device cisco-phone storm-control broadcast level pps 1k storm-control multicast level pps 2k storm-control action shutdown storm-control action trap spanning-tree portfast spanning-tree bpduguard enable spanning-tree guard root ! [download] Outputs: `FastEthernet1/0/3 FastEthernet1/0/4` [download]	[reply] [d/l] [select]
Re: search for a string and return previous relating string if found by NetWallah (Canon) on Dec 06, 2017 at 19:54 UTC
Try this: `perl -nE "m/^interface (\S+)/ and $int=$1; m/ spanning-tree guard root +/ and print qq\|$int $_\|" YOUR-FILE.txt` [download] prints: `FastEthernet1/0/3 spanning-tree guard root` [download] Somewhat simple-minded, but should do the trick. All power corrupts, but we need electricity.	[reply] [d/l] [select]
Re: search for a string and return previous relating string if found by hippo (Archbishop) on Dec 06, 2017 at 17:14 UTC
Sounds fairly straightforward. What did you try and in what way did it fail?	[reply]
Re^2: search for a string and return previous relating string if found by Anonymous Monk on Dec 06, 2017 at 18:15 UTC
you caught me out ;-] if have been using powershell select-string, but am having issues with it searching between the !! delimeters in the text files. using a context produces the lines above or below the match, but this is always variable as the code is different on each section of the input file. `Select-String -Pattern "" -context 2 *.txt` I use a basic perl script to search through for single matches but this stuff is beyond my grasp of Perl	[reply] [d/l]
Re: search for a string and return previous relating string if found by poj (Abbot) on Dec 06, 2017 at 20:10 UTC
I have the following text in many files Are all the files in one directory and do the filenames have a pattern ? poj	[reply]
Re^2: search for a string and return previous relating string if found by Anonymous Monk on Dec 07, 2017 at 11:27 UTC
the files are all in one folder, the only unique identifier of the files is they are all .txt	[reply]
Re^3: search for a string and return previous relating string if found by poj (Abbot) on Dec 07, 2017 at 16:12 UTC
In that case then glob would find the files `#!/usr/bin/perl use strict; my $dir = 'c:/temp/tmp'; # directory to search my @files = glob("$dir/.txt"); for my $filename (@files){ my $lineno = 0; print "Scanning $filename ..\n"; open IN,'<',$filename or die "Could not open $filename : $!"; my $iface; while (<IN>){ ++$lineno; if (/^interface\s+(.)/){ $iface = $1; } if (/spanning-tree guard/){ print "$filename,$lineno,$iface,$_"; $iface = ''; } } }` [download] poj	[reply] [d/l]
Re^4: search for a string and return previous relating string if found by haukex (Archbishop) on Dec 07, 2017 at 18:33 UTC