How to Display Characters Between Two Strings – Shell Scripting

shellshell-script

I want to display all the characters in a file between strings "xxx" and "yyy" (the quotes are not part of the delimiters). How can I do that ? For example, if i have input "Hello world xxx this is a file yyy", the output should be " this is a file "

Best Answer

You can use the pattern matching flag in sed as follows:

echo "Hello world xxx this is a file yyy" | sed 's/.*xxx \(.*\)yyy/\1/'

So .*xxx will match from the beginning up to xxx. This is best shown using grep:

\1 is a 'Remember pattern' that remembers everything that is within \(.*\) so from xxx up to yyy but not yyy.

Finally the remembered string is printed.

Related Solutions

Shell – How to get a string between two special characters using Shell

$ expr /home/oracle/ggs/text.ext : '/home/\(.*\)/'
oracle/ggs

That returns the part after /home/ and before the last /.

Other possible approaches that will fulfil your requirements:

$ echo /home/oracle/ggs/text.ext | cut -d/ -f3,4
oracle/ggs
$ echo /home/oracle/ggs/text.ext | cut -c 7-16
oracle/ggs
$ echo oracle/ggs
oracle/ggs

Shell – Extracting strings from between special characters

sed -ne's/<\([^>"]*\("[^"]*"\)*\)*\)*>//g;/./p' <infile >outfile

...with GNU or BSD seds:

sed -Ene's/<([^>"]*("[^"]*")*)*>//g;/./p' <infile >outfile

Here's something a little more complicated as a proof of concept:

url='http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags'
curl -s  "$url"   |
sed -Ene:n -etD   \
        -e's/ ?[^ "]*"[^"]*"//g;/"/'bN  \
        -e's/[[:space:]]*($|<)/\n\1/'   \
        -e'/^Moderator.s Note/q'        \
        -e'/.\n/P;/\n</!t'        -e:D  \
        -e'/\n/D;/^<script>/!s/>/&\n/'  \
        -e'/\n/!s/<\/script>/\n/' -e:N  \
        -e'/\n/!{N;s///;}' -e//tD -etn

the hardest part is filtering out all of the javascript

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RegEx match open tags except XHTML self-contained tags
up vote
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I need to match all of these opening tags:
&lt;p&gt;
&lt;a&gt;
But not these:
&lt;br /&gt;
&lt;hr /&gt;
I came up with this and wanted to make sure I've got it right. I am only capturing t
he
a-z
.
&lt;([a-z]+) *[^/]*?&gt;
I believe it says:
Find a less-than, then
Find (and capture) a-z one or more times, then
Find zero or more spaces, then
Find any character zero or more times, greedy, except
/
, then
Find a greater-than
Do I have that right? And more importantly, what do you think?
html
regex
xhtml
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May 26 '12 at 20:37
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                                35 Answers
35
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You can't parse [X]HTML with regex. Because HTML can't be parsed by regex. Regex is
not a tool that can be used to correctly parse HTML. As I have answered in HTML-and-
regex questions here so many times before, the use of regex will not allow you to co
nsume HTML. Regular expressions are a tool that is insufficiently sophisticated to u
nderstand the constructs employed by HTML. HTML is not a regular language and hence
cannot be parsed by regular expressions. Regex queries are not equipped to break dow
n HTML into its meaningful parts. so many times but it is not getting to me. Even en
hanced irregular regular expressions as used by Perl are not up to the task of parsi
ng HTML. You will never make me crack. HTML is a language of sufficient complexity t
hat it cannot be parsed by regular expressions. Even Jon Skeet cannot parse HTML usi
ng regular expressions. Every time you attempt to parse HTML with regular expression
s, the unholy child weeps the blood of virgins, and Russian hackers pwn your webapp.
 Parsing HTML with regex summons tainted souls into the realm of the living. HTML an
d regex go together like love, marriage, and ritual infanticide. The &lt;center> can
not hold it is too late. The force of regex and HTML together in the same conceptual
 space will destroy your mind like so much watery putty. If you parse HTML with rege
x you are giving in to Them and their blasphemous ways which doom us all to inhuman
toil for the One whose Name cannot be expressed in the Basic Multilingual Plane, he
comes. HTML-plus-regexp will liquify the nerves of the sentient whilst you observe,
 your psyche withering in the onslaught of horror. Rege̿̔̉x-based HTML parsers are t
he cancer that is killing StackOverflow
it is too late it is too late we cannot be saved
 the trangession of a chi͡ld ensures regex will consume all living tissue (except fo
r HTML which it cannot, as previously prophesied)
dear lord help us how can anyone survive this scourge
 using regex to parse HTML has doomed humanity to an eternity of dread torture and s
ecurity holes
using rege
x as a tool to process HTML establishes a brea
ch between this world
 and the dread realm of c͒ͪo͛ͫrrupt entities (like SGML entities, but
more corrupt) a mere glimp
se of the world of reg
ex parsers for HTML will ins
tantly transport a p
rogrammer's consciousness i
nto a w
orl
d of ceaseless screaming, he comes
, the pestilent sl
ithy regex-infection wil
l devour your HT
ML parser, application and existence for all time like Visual Basic only worse
he comes he com
es
do not fi
ght h
e com̡e̶s, ̕h̵i
s un̨ho͞ly radiańcé de
stro҉ying all enli̍̈́̂̈́ghtenment, HTML tags
lea͠ki̧n͘g fr̶ǫm ̡yo͟ur eye͢s̸ ̛l̕ik͏e liq
uid p
ain, the song of re̸gular expre
ssion parsing
will exti
nguish the voices of mor
tal man from the sp
here I can see it can you see ̲͚̖͔̙î̩́t̲͎̩̱͔́̋̀ it is beautiful t
he f
inal snuf
fing o
f the lie
s of Man ALL IS LOŚ͖̩͇̗̪̏̈́T A
LL IS L
OST th
e pon̷y he come
s he c̶̮om
es he co
me
s t
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 ich
or permeat
es al
l MY FAC
E MY FACE ᵒh god n
o NO NOO̼
OO N
Θ stop t
he an*̶͑̾̾̅ͫ͏̙̤g͇̫͛͆̾ͫ̑͆l͖͉̗̩̳̟̍ͫͥͨ
e̠̅s
 ͎a̧͈͖r̽̾̈́͒͑e
 n
ot rè̑ͧ̌aͨl̘̝̙̃ͤ͂̾̆ ZA̡͊͠͝LGΌ ISͮ̂҉̯͈͕̹̘̱ T
O͇̹̺ͅƝ̴ȳ̳ TH̘
Ë͖́̉ ͠P̯͍̭O̚N̐Y̡ H̸̡̪̯ͨ͊̽̅̾̎Ȩ̬̩̾͛ͪ̈́̀́͘ ̶̧̨̱̹̭̯ͧ̾ͬC̷̙̲̝͖ͭ̏ͥͮ͟Oͮ͏̮̪̝͍M̲̖͊̒ͪͩͬ̚̚͜Ȇ̴̟̟͙̞ͩ͌͝
S̨̥̫͎̭ͯ̿̔̀ͅ
Have you tried using an XML parser instead?

Best Answer

Related Solutions

Shell – How to get a string between two special characters using Shell

Shell – Extracting strings from between special characters

Related Question