Printing Lines between two Two Pattern-CodePudding

I have a file like this:

text1
text2
Pattern1
text3
text4
Pattern1
text5
text2
text6
Pattern1
text7
text8
Pattern2
text2
text9
text10
text2
Pattern1
text11
text12
Pattern1
text13
text14
Pattern1
text15
text16
Pattern2
text1
text2
Pattern1
text3
text4
Pattern1
text5
text6
Pattern1
text7
text2
text8
Pattern2
text21
text22

I want to print ONLY

Pattern1
text7
text8
Pattern2
Pattern1
text15
text16
Pattern2
Pattern1
text7
text2
text8
Pattern2

i.e. if Pattern1 is followed by Pattern2, then print lines between Pattern1 and Pattern2. I don't want lines if Pattern1 is followed by Pattern1.

An awk command is highly appreciated.

I was trying like:

awk '/Pattern1/,/Pattern2' file \> output

but it gives all the lanes that appear between two successive Pattern1 also.

CodePudding user response：

You may use this awk:

awk '
/^Pattern1$/ {s = $0 ORS; next}
s != "" {s = s $0 ORS}
/^Pattern2$/ {printf "%s", s; s = ""}
' file

Pattern1
text7
text8
Pattern2
Pattern1
text15
text16
Pattern2
Pattern1
text7
text2
text8
Pattern2

CodePudding user response：

$ awk '
/Pattern1/,/Pattern2/ {   # between markers
    if(/Pattern1/)        # at the begin marker...
        b=$0              # ... reset buffer
    else 
        b=b ORS $0        # or keep on buffering
    if(/Pattern2/)        # at the end marker...
        print b           # ... it is time to output
}' file

head -4 of output:

Pattern1
text7
text8
Pattern2
...