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

Hi Monks...

I am fairly new to PERL. I am attempting to read a text file, parse out a section then re-format the same information. I've used the flip-flop operator and I can pull out pieces. However I first need to pull a section based on the line "1. OPS 7554 REV " . Once I find this line, I need to back up to a known point and pull everything including this line plus some below the pattern found. I've included a piece of the file to hopefully better explain what I'm attempting to accomplish.

Thank you!

The file is quite large, her's a line that contains my first search pattern. This pattern is repeated with similarities several times. 

1. OPS 7554 REV  22590 R+ 11                           EDTSON:2007/26
2.                                                     PIPSET:2039/02
3. ASCENDING NODE TIME: 1955/33 (71733)                EDTSOF:2057/02

[download]

*****Update*****

All, thanks for the help and advice. Yes, I am new to both.

I've included more of the file that I'm attempting to pull out.

The data above "1. OPS 7554 REV 22588 R+ 09 EDTSON:1646/46", contains much of the data that I need to pull however, my problem at this moment has been splitting this large into the chunk that I'm looking for. For instance, in this case I'm looking for "OPS 7554 Rev # 22588". I only want the data that pertains to that ops and rev #. That data below "1. OPS 7554 REV  22588 R+ 09                           EDTSON:1646/46", is necessary information up to the "****End of Main Memory Event *****".

I did mention the file is quite large but to keep that in perspective, it's in the order Kbs...really not that large and certainly within memory regions. 

LOAD NAME                          ADDRESSES   CHECKSUM      ENDLINE
---------                          ---------   --------      -------
LOGM15422588....................   0500-06FF     987D      03/17:36:15
LOMM15422588....................   0100-04FF     524B      03/17:36:05
LSCT25422588....................   0000-0095     F713      03/17:36:11
LSCT15422588....................   0000-0095     773B      03/17:36:12
LODM15422588....................   0700-075B     607F      29/13:08:46
LSPR15422599....................   0000-01E0     6CCF      29/13:02:49
LSSC15422599....................   0000-00B3     D6E0      29/13:10:37
LSPR25422600....................   0000-01E0     6CCF      29/13:02:49
LSSC25422600....................   0000-00B3     D6E0      29/13:10:37

0001 2008064/16:17:20   ;   CMD ORTDON CH3 TFLS EN ON SRC=OMM      ;02
+7E; Start Xmit RTD TFLS on CH3
0002 2008064/16:34:28   ;   CMD OFRDON PR3 TL SRC=OMM              ;02
+80; Start SDF Record on PR3
0003 2008064/16:45:46   ;*********************************************
+**********************
0004 2008064/16:45:46   ; ACQ Start for DMSP-54 for rev 22588 (R+09) a
+t POGO-A
0005 2008064/16:45:46   ;     Rise        at  2008064 / 16:50:46   
0006 2008064/16:45:46   ;     Biased Rise at  2008064 / 16:50:46   
0007 2008064/16:45:46   ;     SOCC Link name is S1                 
0008 2008064/16:45:46   ;*********************************************
+**********************
0009 2008064/16:45:46   SET MODE=RLT REV=22588 SITE=POGO ANT=A  TYPE=A
+IU; Set mode
0010 2008064/16:45:46   SET LINK=S1                                ;
0011 2008064/16:45:46   DATAPATH SPATH2 TYPE=EST                   ; S
+et up EST path for Schriever Domsat
0012 2008064/16:45:46   DATAPATH SPATH2 TYPE=STDS                  ; S
+et up STD path for Schriever Domsat
0013 2008064/16:46:00   ;   CMD ORECOF PR3 SRC=OMM                 ;02
+82; Stop  SDF Record on PR3
0014 2008064/16:46:20   ;   CMD OSRDON PR2 SRC=OMM                 ;02
+84; Start SDS Record on PR2
0015 2008064/16:46:31   CONFIG TLM=SPATH2 CMD=SPATH2               ; L
+ink Primary CC to Cmd and Tlm paths
0016 2008064/16:46:31   SCH SUSPEND                                ;
0017 2008064/16:46:31   ;Configure AFSCN resources, issue TAKECMD dire
+ctive
0018 2008064/16:46:31   EQP AIU ACQ VEH=54 SLAVE=LOC TIME=16:50:46 ;
0019 2008064/16:46:31   CMDM PASS=START                            ; I
+nitialize DDCP PASS mode
0020 2008064/16:46:31   AUTH ABORT                                 ; C
+lear DDCP command queue
0021 2008064/16:46:31   AUTH KG                                    ; S
+elect command KG
0022 2008064/16:46:31   AUTH TVOUTPUT=ENA                          ; E
+nable continuous T & V output
0023 2008064/16:46:31   AUTH TIMEOUT 6                             ;
0024 2008064/16:46:31   CMDVER ON                                  ; E
+nable AV, CV, TV verification
0025 2008064/16:46:31   LIMITS MSG=ON                              ; E
+nable  limits messages          
0026 2008064/16:46:46   ;   CMD  ED2NLK SRC=SCT                    ;00
+46; T/M link 2 on
0027 2008064/16:46:46   ;   CMD  ED2NLK SRC=SCT                    ;00
+46; T/M link 2 on
0028 2008064/16:50:20   ;   CMD ORECOF PR1 SRC=OMM                 ;02
+86; Stop  SDS Record on PR1
0029 2008064/16:50:46   ;*********************************************
+**********************
0030 2008064/16:50:46   ; End of ACQ_S Event for DMSP-54 for rev 22588
+ (R+09) at POGO-A
0031 2008064/16:50:46   ;*********************************************
+**********************
0032 2008064/16:51:50   AUTH CPAM                                  ; P
+erform crypto-sync, PAMSET
0033 2008064/16:52:05   CMD OPBKHI PR1 CH1 EN                      ; S
+tart SDS Playback on CH1 from PR1
0034 2008064/16:52:06   CMD PIPSETOR OF OD PROG                    ; P
+IP mode set for 10K OLS dump
0035 2008064/16:52:31   CMD OGAINF                                 ; G
+ain off
0036 2008064/16:52:31   CMD OMACWC '0200'X                         ; W
+ord count
0037 2008064/16:52:31   CMD OMACAD '00'X                           ; S
+tart address for load
0038 2008064/16:52:31   CMD OMACPL '05'X                           ; L
+oad page
0039 2008064/16:52:31   LOAD LOGM15422588                          ; S
+tart load for CPU=1  (Source Proc day064)      
0040 2008064/16:52:51   ;                                          ; W
+ait for load to complete
0041 2008064/16:52:51   AUTH CPAM                                  ; P
+erform crypto-sync PAMSET
0042 2008064/16:52:56   CMD OMACWC '0200'X                         ; W
+ord count
0043 2008064/16:52:56   CMD OMACAD '00'X                           ; S
+tart address for dump
0044 2008064/16:52:56   CMD OMACPD '05'X                           ; D
+ump page
0045 2008064/16:53:16   ;                                          ; W
+ait for dump to complete
0046 2008064/16:53:16   DMPCMPR SEL LOGM15422588                   ; D
+ump compare    
0047 2008064/16:53:21   ;                                          ; W
+ait for dump compare to complete  
0048 2008064/16:53:21   CMD OPAGEA '00'X                           ; S
+et starting address within page
0049 2008064/16:53:21   CMD OPAGEN '05'X                           ; S
+et page number and memory on
0050 2008064/16:53:26   ;                                          ; W
+ait for OPAGEA and OPAGEN
0051 2008064/16:53:26   CMD ODMPAL                                 
0052 2008064/16:53:36   CMD OCLRAL                                 
0053 2008064/16:54:01   CMD OMAINF                                 ; M
+ain off
0054 2008064/16:54:01   CMD OMACWC '0000'X                         ; W
+ord count
0055 2008064/16:54:01   CMD OMACAD '00'X                           ; S
+tart address for load 
0056 2008064/16:54:01   CMD OMACPL '01'X                           ; L
+oad page
0057 2008064/16:54:01   LOAD LOMM15422588                          ; S
+tart load to cpu 1  (Proc = N/A)
0058 2008064/16:54:26   ;                                          ; W
+ait for load to complete
0059 2008064/16:54:26   AUTH CPAM                                  ; P
+erform crypto-sync PAMSET
0060 2008064/16:54:31   CMD OMACWC '0000'X                         ; W
+ord count
0061 2008064/16:54:31   CMD OMACAD '00'X                           ; S
+tart address for dump
0062 2008064/16:54:31   CMD OMACPD '01'X                           ; D
+ump page
0063 2008064/16:55:01   ;                                          ; W
+ait for dump to complete
0064 2008064/16:55:01   DMPCMPR SEL LOMM15422588                   ; D
+ump compare to verify    
0065 2008064/16:55:06   ;                                          ; W
+ait for verify to complete  
0066 2008064/16:55:06   CMD OPAGEA '00'X                           ; S
+et starting address within page
0067 2008064/16:55:06   CMD OPAGEN '01'X                           ; S
+et page number and memory on
0068 2008064/16:55:11   ;                                          ; W
+ait for OPAGEA and OPAGEN
0069 2008064/16:55:11   CMD OPBKHI PR3 CH2 EN                      ; S
+tart SDF Playback (TL) on CH2 from PR3
0070 2008064/16:55:53   CMD ORECOF PR1                             ; S
+top  SDS Playback on CH1 from PR1
0071 2008064/16:56:25   CMD PIPSETOR OF C2  PROG                   ; P
+IP mode set to 10k SCP dump
0072 2008064/16:56:50   CMD STSBTL '0000'X '0095'X CPU=2           ; C
+ommand time subtable load
0073 2008064/16:56:50   LOAD LSCT25422588                          ; S
+tart load for cpu 2  (Proc=N/A)
0074 2008064/16:57:20   ;                                          ; W
+ait for load to complete
0075 2008064/16:57:20   AUTH CPAM                                  ; P
+erform crypto-sync PAMSET
0076 2008064/16:57:25   CMD VERDMP CPU=2                           ; V
+erification dump
0077 2008064/16:57:40   ;                                          ; W
+ait for dump to complete
0078 2008064/16:57:40   DMPCMPR SEL LSCT25422588                   ; D
+ump compare    
0079 2008064/16:57:45   ;                                          ; W
+ait for dump compare to complete  
0080 2008064/16:57:45   CMD STSIGO '0000'X CPU=2                   ; S
+et index and go
0081 2008064/16:57:50   CMD PIPSETOR OF C1  PROG                   ; P
+IP mode set to 10k SCP dump
0082 2008064/16:57:50   ;                                          ; W
+ait for STSIGO and STSBTN
0083 2008064/16:58:15   CMD STSBTL '0000'X '0095'X CPU=1           ; C
+ommand time subtable load
0084 2008064/16:58:15   LOAD LSCT15422588                          ; S
+tart load for cpu 1  (Proc=N/A)
0085 2008064/16:58:45   ;                                          ; W
+ait for load to complete
0086 2008064/16:58:45   AUTH CPAM                                  ; P
+erform crypto-sync PAMSET
0087 2008064/16:58:50   CMD VERDMP CPU=1                           ; V
+erification dump
0088 2008064/16:59:05   ;                                          ; W
+ait for dump to complete
0089 2008064/16:59:05   DMPCMPR SEL LSCT15422588                   ; D
+ump compare    
0090 2008064/16:59:10   ;                                          ; W
+ait for dump compare to complete  
0091 2008064/16:59:10   CMD STSIGO '0000'X CPU=1                   ; S
+et index and go
0092 2008064/16:59:15   CMD PIPSETOR OF OD PROG                    ; P
+IP mode set for 10K OLS dump
0093 2008064/16:59:15   ;                                          ; W
+ait for STSIGO and STSBTN
0094 2008064/16:59:40   CMD OMACWC '005C'X                         ; W
+ord count
0095 2008064/16:59:40   CMD OMACAD '00'X                           ; S
+tart address for load
0096 2008064/16:59:40   CMD OMACPL '07'X                           ; L
+oad page
0097 2008064/16:59:40   LOAD LODM15422588                          ; S
+tart LODM load for CPU 1 
0098 2008064/16:59:55   ;                                          ; W
+ait for load to complete
0099 2008064/16:59:55   AUTH CPAM                                  ; P
+erform crypto-sync PAMSET
0100 2008064/17:00:00   CMD OMACWC '005C'X                         ; W
+ord count
0101 2008064/17:00:00   CMD OMACAD '00'X                           ; S
+tart address for dump
0102 2008064/17:00:00   CMD OMACPD '07'X                           ; D
+ump page
0103 2008064/17:00:10   ;                                          ; W
+ait for dump to complete
0104 2008064/17:00:10   DMPCMPR SEL LODM15422588                   ; D
+ump compare    
0105 2008064/17:00:15   ;                                          ; W
+ait for dump compare to complete  
0106 2008064/17:01:11   CMD ORECOF PR3                             ; S
+top  SDF Playback (TL) on CH2 from PR3
0107 2008064/17:01:16       CMD ORTDON CH3 TFLS CL ON SRC=OMM      ;01
+00; Start Xmit RTD TFLS on CH3
0108 2008064/17:04:21   CMD PIPSETOR OS TC PROG                    ; P
+IP mode set to OS TC PRESET
0109 2008064/17:04:56   CMD EDTSOF                                 ; T
+/M LINKS OFF - EDT'S
0110 2008064/17:05:01   AUTH LOCK                                  ; L
+ock T&V Values
0111 2008064/17:06:20   SCH  SUSPEND                               ; V
+erify LOS     
0112 2008064/17:06:20   ;*********************************************
+**********************
0113 2008064/17:06:20   ; ACQ End for DMSP-54 for rev 22588 (R+09) at 
+POGO-A
0114 2008064/17:06:20   ;     Fade        at  2008064 / 17:06:20   
0115 2008064/17:06:20   ;     Biased_Fade at  2008064 / 17:06:20   
0116 2008064/17:06:20   ;*********************************************
+**********************
0117 2008064/17:06:20   CMDM PASS=STOP                             ; T
+erminate DDCP PASS
0118 2008064/17:06:20   TERM SPATH2 TYPE=EST                       ; T
+erminate EST Path at Primary CC (S )
0119 2008064/17:06:20   TERM SPATH2 TYPE=STDS                      ; T
+erminate STD Path at Primary CC (S )
0120 2008064/17:06:20   SCH  SUSPEND                               ; P
+roceed when ready for XFERs
0121 2008064/17:06:20   XFER SPATH2                                ; I
+nitiate  STD XFER at Primary CC (S )
0122 2008064/17:06:20   SCH  SUSPEND                               ; V
+erify completion of XFERs
0123 2008064/17:06:20   TERM SPATH2 TYPE=STD                       ; T
+erminate STD XFER at Primary CC (S )
0124 2008064/17:06:20   CFG FLUSH                                  ; F
+lush configuration
0125 2008064/17:06:20   ;*********************************************
+**********************
0126 2008064/17:06:20   ; End of ACQ End Event for DMSP-54 for rev 225
+88 (R+09) at POGO-A
0127 2008064/17:06:20   ;*********************************************
+**********************


 1. OPS 7554 REV  22588 R+ 09                           EDTSON:1646/46
 2.                                                     PIPSET:1718/20
 3. ASCENDING NODE TIME: 1631/40 (59500)                EDTSOF:1736/20
 4. CONTACT SITE: POGO-A
 5.   -RISE 1650/46 (60646) AZ  58.8 BIAS 00/00      ASC-RISE:0019/06 
+(01146) 
 6.   -MID  1658/33 (61113) AZ 337.9 EL 60.3
 7.   -FADE 1706/20 (61580) AZ 256.9 BIAS 00/00      ASC-FADE:0034/40 
+(02080) 
 8.
 9. CONTACT WINDOWS CREATED BY OBSCURA:
10.  1/   1651/06 - 1705/30      5/                          VES: 1812
+/29
11.  2/                          6/                          VED: 1812
+/29
12.  3/                          7/                          
13.  4/                          8/                          

14. SOLAR ARRAY DRIVE:
15.   -ACQ+2: 1652/46  SAD ANGLE 281.3  SUBLONG 343.5  SUBLAT 72.5
16.   -MAXEL: 1658/33  SAD ANGLE 260.8  SUBLONG  76.7  SUBLAT 79.9

17. -EDT1:OFF                 -EDT2:ON
18. -DT1: OFF     DT2: OFF     DT3: ON      DT4: OFF

19.  -MEMORY ADDRESSES :   STSCT-1    STSCT-2     MAIN       GAIN
20.  RISE/FADE         :  0047/0000  0047/0000  0288/0102  0528/0542

21. PLAYBACKS:            START      TOTAL      ACTUAL    COMPLETE C/E
+ RATE   START/STOP
                                    DURATION   DURATION               
+           LINE#
22. -PR1-  S  CH1 DT1    1652/05     03/48       03/35     1655/53  E 
+  HI     0033/0071
23. -PR3-  TL CH2 DT2    1655/11     06/00       05/47     1701/11  E 
+  HI     0070/0107

**** Main Memory Commands During Contact For 22588 (R+09) POGO-A ****
0108  2008064/17:01:16   CMD ORTDON CH3 TFLS CL ON SRC=OMM          ;0
+100; Start Xmit RTD TFLS on CH3
**** End of Main Memory Commands ****


0128 2008064/17:07:36   ;   CMD OFRDON PR4 LF SRC=OMM              ;01
+02; Start SDF Record on PR4
0129 2008064/17:08:12   ;   CMD ORTDON CH3 LFTS CL ON SRC=OMM      ;01
+04; Start Xmit RTD LFTS on CH3
0130 2008064/17:10:32   ;   CMD ORECOF PR4 SRC=OMM                 ;01
+06; Stop  SDF Record on PR4
0131 2008064/17:12:32   ;   CMD ORTDON CH3 LFTS EN ON SRC=OMM      ;01
+08; Start Xmit RTD LFTS on CH3
0132 2008064/17:18:20   ;   CMD PIPSETOR OS TC PROG  SRC=SCT       ;00
+00; PIP mode set to OS TC PROG
0133 2008064/17:18:20   ;   CMD PIPSETOR OS TC PROG  SRC=SCT       ;00
+00; PIP mode set to OS TC PROG
0134 2008064/17:36:20   ;   CMD EDTSOF SRC=SCT                     ;00
+03; T/M links off - EDT's
0135 2008064/17:36:20   ;   CMD EDTSOF SRC=SCT                     ;00
+03; T/M links off - EDT's
0136 2008064/17:36:56   ;   CMD ORTDON CH3 LFTS CL ON SRC=OMM      ;01
+0A; Start Xmit RTD LFTS on CH3
0137 2008064/17:38:56   ;   CMD OFRDON PR4 LF SRC=OMM              ;01
+0C; Start SDF Record on PR4
0138 2008064/17:46:40   ;   CMD ORECOF PR4 SRC=OMM                 ;01
+0E; Stop  SDF Record on PR4
0139 2008064/17:59:16   ;   CMD ORTDON CH3 TFLS EN ON SRC=OMM      ;01
+10; Start Xmit RTD TFLS on CH3
0140 2008064/18:23:32   ;   CMD OFRDON PR3 TL SRC=OMM              ;01
+12; Start SDF Record on PR3
0141 2008064/18:26:09   ;*********************************************
+**********************
0142 2008064/18:26:09   ; ACQ Start for DMSP-54 for rev 22589 (R+10) a
+t POGO-A
0143 2008064/18:26:09   ;     Rise        at  2008064 / 18:31:09   
0144 2008064/18:26:09   ;     Biased Rise at  2008064 / 18:31:09   
0145 2008064/18:26:09   ;     SOCC Link name is S1                 
0146 2008064/18:26:09   ;*********************************************
+**********************
0147 2008064/18:26:09   SET MODE=RLT REV=22589 SITE=POGO ANT=A  TYPE=A
+IU; Set mode
0148 2008064/18:26:09   SET LINK=S1                                ;
0149 2008064/18:26:09   DATAPATH SPATH3 TYPE=EST                   ; S
+et up EST path for Schriever Domsat
0150 2008064/18:26:09   DATAPATH SPATH3 TYPE=STDS                  ; S
+et up STD path for Schriever Domsat
0151 2008064/18:26:12   ;   CMD OSRDON PR1 SRC=OMM                 ;01
+14; Start SDS Record on PR1
0152 2008064/18:26:54   CONFIG TLM=SPATH3 CMD=SPATH3               ; L
+ink Primary CC to Cmd and Tlm paths
0153 2008064/18:26:54   SCH SUSPEND                                ;
0154 2008064/18:26:54   ;Configure AFSCN resources, issue TAKECMD dire
+ctive
0155 2008064/18:26:54   EQP AIU ACQ VEH=54 SLAVE=LOC TIME=18:31:09 ;
0156 2008064/18:26:54   CMDM PASS=START                            ; I
+nitialize DDCP PASS mode
0157 2008064/18:26:54   AUTH ABORT                                 ; C
+lear DDCP command queue
0158 2008064/18:26:54   AUTH KG                                    ; S
+elect command KG
0159 2008064/18:26:54   AUTH TVOUTPUT=ENA                          ; E
+nable continuous T & V output
0160 2008064/18:26:54   AUTH TIMEOUT 6                             ;
0161 2008064/18:26:54   CMDVER ON                                  ; E
+nable AV, CV, TV verification
0162 2008064/18:26:54   LIMITS MSG=ON                              ; E
+nable  limits messages          
0163 2008064/18:27:09   ;   CMD  ED2NLK SRC=SCT                    ;00
+04; T/M link 2 on
0164 2008064/18:27:09   ;   CMD  ED2NLK SRC=SCT                    ;00
+04; T/M link 2 on
0165 2008064/18:30:12   ;   CMD ORECOF PR2 SRC=OMM                 ;01
+16; Stop  SDS Record on PR2
0166 2008064/18:30:52   ;   CMD ORECOF PR3 SRC=OMM                 ;01
+18; Stop  SDF Record on PR3
0167 2008064/18:31:09   ;*********************************************
+**********************
0168 2008064/18:31:09   ; End of ACQ_S Event for DMSP-54 for rev 22589
+ (R+10) at POGO-A
0169 2008064/18:31:09   ;*********************************************
+**********************
0170 2008064/18:32:13   AUTH CPAM                                  ; P
+erform crypto-sync, PAMSET
0171 2008064/18:32:28   CMD OPBKHI PR3 CH2 EN                      ; S
+tart SDF Playback (TL) on CH2 from PR3
0172 2008064/18:32:38   CMD OPBKHI PR2 CH1 EN                      ; S
+tart SDS Playback on CH1 from PR2
0173 2008064/18:36:22   CMD ORECOF PR3                             ; S
+top  SDF Playback (TL) on CH2 from PR3
0174 2008064/18:36:24   CMD ORECOF PR2                             ; S
+top  SDS Playback on CH1 from PR2
0175 2008064/18:36:53   CMD OPBKHI PR4 CH2 EN                      ; S
+tart SDF Playback (LF) on CH2 from PR4
0176 2008064/18:40:28   CMD ORECOF PR4                             ; S
+top  SDF Playback (LF) on CH2 from PR4
0177 2008064/18:42:28       CMD OFRDON PR3 TF SRC=OMM              ;01
+1A; Start SDF Record on PR3
0178 2008064/18:43:32   CMD EDTSOF                                 ; T
+/M LINKS OFF - EDT'S
0179 2008064/18:43:37   AUTH LOCK                                  ; L
+ock T&V Values
0180 2008064/18:44:12       CMD ORTDON CH3 TFLS CL ON SRC=OMM      ;01
+1C; Start Xmit RTD TFLS on CH3
0181 2008064/18:46:37   SCH  SUSPEND                               ; V
+erify LOS     
0182 2008064/18:46:37   ;*********************************************
+**********************
0183 2008064/18:46:37   ; ACQ End for DMSP-54 for rev 22589 (R+10) at 
+POGO-A
0184 2008064/18:46:37   ;     Fade        at  2008064 / 18:46:37   
0185 2008064/18:46:37   ;     Biased_Fade at  2008064 / 18:46:37   
0186 2008064/18:46:37   ;*********************************************
+**********************
0187 2008064/18:46:37   CMDM PASS=STOP                             ; T
+erminate DDCP PASS
0188 2008064/18:46:37   TERM SPATH3 TYPE=EST                       ; T
+erminate EST Path at Primary CC (S )
0189 2008064/18:46:37   TERM SPATH3 TYPE=STDS                      ; T
+erminate STD Path at Primary CC (S )
0190 2008064/18:46:37   SCH  SUSPEND                               ; P
+roceed when ready for XFERs
0191 2008064/18:46:37   XFER SPATH3                                ; I
+nitiate  STD XFER at Primary CC (S )
0192 2008064/18:46:37   SCH  SUSPEND                               ; V
+erify completion of XFERs
0193 2008064/18:46:37   TERM SPATH3 TYPE=STD                       ; T
+erminate STD XFER at Primary CC (S )
0194 2008064/18:46:37   CFG FLUSH                                  ; F
+lush configuration
0195 2008064/18:46:37   ;*********************************************
+**********************
0196 2008064/18:46:37   ; End of ACQ End Event for DMSP-54 for rev 225
+89 (R+10) at POGO-A
0197 2008064/18:46:37   ;*********************************************
+**********************


 1. OPS 7554 REV  22589 R+ 10                           EDTSON:1827/09
 2.                                                     PIPSET:1858/37
 3. ASCENDING NODE TIME: 1813/37 (65617)                EDTSOF:1916/37
 4. CONTACT SITE: POGO-A
 5.   -RISE 1831/09 (66669) AZ  81.4 BIAS 00/00      ASC-RISE:0017/32 
+(01052) 
 6.   -MID  1838/52 (67132) AZ   2.3 EL 53.8
 7.   -FADE 1846/37 (67597) AZ 283.3 BIAS 00/00      ASC-FADE:0033/00 
+(01980) 
 8.
 9. CONTACT WINDOWS CREATED BY OBSCURA:
10.  1/   1831/29 - 1844/06      5/                          VES: 1954
+/24
11.  2/                          6/                          VED: 1954
+/24
12.  3/                          7/                          
13.  4/                          8/                          

14. SOLAR ARRAY DRIVE:
15.   -ACQ+2: 1833/09  SAD ANGLE 286.8  SUBLONG   1.3  SUBLAT 67.6
16.   -MAXEL: 1838/52  SAD ANGLE 266.5  SUBLONG  67.3  SUBLAT 81.3

17. -EDT1:OFF                 -EDT2:ON
18. -DT1: OFF     DT2: OFF     DT3: ON      DT4: OFF

19.  -MEMORY ADDRESSES :   STSCT-1    STSCT-2     MAIN       GAIN
20.  RISE/FADE         :  0005/0005  0005/0005  011A/011E  0528/053E

21. PLAYBACKS:            START      TOTAL      ACTUAL    COMPLETE C/E
+ RATE   START/STOP
                                    DURATION   DURATION               
+           LINE#
22. -PR2-  S  CH1 DT1    1832/38     03/46       03/33     1836/24  E 
+  HI     0173/0175
23. -PR3-  TL CH2 DT2    1832/28     03/54       03/41     1836/22  E 
+  HI     0172/0174
24. -PR4-  LF CH2 DT2    1836/53     03/35       03/22     1840/28  E 
+  HI     0176/0177

**** Main Memory Commands During Contact For 22589 (R+10) POGO-A ****
0178  2008064/18:42:28   CMD OFRDON PR3 TF SRC=OMM                  ;0
+11A; Start SDF Record on PR3
0182  2008064/18:44:12   CMD ORTDON CH3 TFLS CL ON SRC=OMM          ;0
+11C; Start Xmit RTD TFLS on CH3
**** End of Main Memory Commands ****

[download]

Replies are listed 'Best First'.
Re: searching across a file then parsing
by Marshall (Canon) on Feb 17, 2012 at 04:37 UTC
    The 3 lines that you included didn't clarify much for me. If you put <code> ... your text here ... </code> tags around file or program text it will come out verbatim and this makes it a lot easier for us to see what you have.

    You say "The file is quite large". If that means its so big that it won't fit into memory, then I would consider using command line grep with the -A and -B options to extract out hunks of stuff that will fit into memory. That should make this "I need stuff before the match" easier. 

    from the grep man page....
Context control:
  -B, --before-context=NUM  print NUM lines of leading context
  -A, --after-context=NUM   print NUM lines of trailing context

    [download]
    Can you show some code of what you have so far? Its really unclear what for example "I need to back up to a known point" means.
[reply]
[d/l]
[select]

      Its really unclear what for example "I need to back up to a known point" means.

      probably seek

[reply]

        This is purely a guess, but I suspect that rather than a character-by-character numerical position change (like that provided by 'seek'), the OP is looking for a "line-by-line cache" - similar to something I did recently.

        I'm going to assume that the file is too big to stuff into a scalar and process with something like /($start.*?$match.*?$end)/ - i.e., that it does indeed need to be read one line at a time. 

        #!/usr/bin/perl
use common::sense;

my $pat1 = "TOP_PATTERN";
my $pat2 = "SEARCH_PATTERN";

my ($flag, $cache);
while (<DATA>){
    if ($flag){
        last if /$pat1/;
        print and next;
    }

    if (/$pat1/){
        $cache = "" and next if $cache;
        $cache .= $_ and next;
    }
    if ($cache){
        $cache .= $_;
        $flag = 1 and print $cache if /$pat2/;
    }
}

__END__
TOP_PATTERN
1
2
3
TOP_PATTERN
4
5
6
SEARCH_PATTERN
7
TOP_PATTERN
8
9

        [download]

        Output:

        TOP_PATTERN
4
5
6
SEARCH_PATTERN
7

        [download]
        -- 
I hate storms, but calms undermine my spirits.
 -- Bernard Moitessier, "The Long Way"
[reply]
[d/l]
[select]
        Seek is a low level critter that only deals with bytes, not lines. And if we are talking about unicode, we aren't even talking about characters since one character could be multiple bytes. I think it is highly unlikely that seek() will play any role at all in the final solution to this problem. It is very rare to use seek in a text file.

        The problem requirements just aren't specified clearly enough here to proceed further without hearing more from the OP.

        I like the idea presented by oko1. But until the OP gives a rule for what to include before the "match", we are just all guessing.

[reply]
        Anonymous, I agree...sorry about that. I've updated it to better explain what I'm attempting to do. Thanks for the help.
[reply]
Re: searching across a file then parsing
by oko1 (Deacon) on Feb 17, 2012 at 01:24 UTC

    I'm going to take a wild guess here... you're not just new to Perl (it's not called 'PERL', by the way), you're new to PerlMonks, right? :) Very important thing here - please pay attention:

    YOU HAVE TO USE CODE TAGS AROUND YOUR CODE.

    Otherwise, it will all come out as one line. Which is what happened. Which is why your question is essentially not answerable - since, as you yourself pointed out above, we need to see the format of your data file.

    Please re-edit your post and put <c> code goes here </c> tags around the code/data part of it. Folks would be happy to help you then, I'm sure. 

    -- 
I hate storms, but calms undermine my spirits.
 -- Bernard Moitessier, "The Long Way"
[reply]

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