Is there a way to search PDF files using the power of grep, without converting to text first in Ubuntu?
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1See also Is there some sort of PDF to text -converter? and Command line tool to search phrases in large number of pdf files. – Gilles 'SO- stop being evil' Jan 31 '11 at 20:01
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1For people comming here via search: If you are willing to convert it first to text files, have a look at How to search contents of multiple pdf files? – Martin Thoma Jan 2 '16 at 22:09
Install the package pdfgrep
, then use the command:
find /path -iname '*.pdf' -exec pdfgrep pattern {} +
——————
Simplest way to do that:
pdfgrep 'pattern' *.pdf
pdfgrep 'pattern' file.pdf
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6This works in mac osx (Mavericks) as well. Install it using brew. Simple. Thanks. – mikiemorales Jan 23 '14 at 1:28
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8Out of curiosity I checked the source of pdfgrep and it uses poppler to extract strings from the pdf. Almost exactly as @wag's answer only pagewise rather than, presumably, the entire document. – Andrew Martin Sep 16 '14 at 11:11
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5
pdfgrep
also has a recursive flag. So this answer could perhaps be reduced to:pdfgrep -R pattern /path/
. Though it might be less effective if it goes through every file even if it isn't a PDF. And I notice that it has issues with international characters such as å, ä and ö. – Rovanion Jan 14 '16 at 12:11 -
1Actually, the
-n
option is a pro for pdfgrep as it allows to include the page number in the output (might be helpful for further processing). – JepZ Nov 10 '17 at 20:18 -
4This answer would be easier to use if it explained which bits of the command are meant to copied literally and which are placeholders. What's
pattern
? What's{}
? What's up with the ` +`? I have no idea upon first reading... so off to the manpage I go, I suppose. – Mark Amery Apr 20 '18 at 14:44
If you have poppler-utils
installed (default on Ubuntu Desktop), you could "convert" it on the fly and pipe it to grep
:
pdftotext my.pdf - | grep 'pattern'
This won't create a .txt file.
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1so .. you extract the text before you grep it which means the answer is "no". – akira Jan 31 '11 at 15:18
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19@akira The OP probably meant "without opening the PDF in a viewer and exporting to text" – Michael Mrozek Jan 31 '11 at 17:36
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5
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6@akira Well, I already said what I think he probably meant; he doesn't want to export to text before processing it. I very much doubt he has a problem with any command that converts to text in any way; there's no reason not to – Michael Mrozek Feb 1 '11 at 5:52
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2@sherrellbc The second argument of
pdftotext
is the filename it should write to. However, by convention, tools typically allow you to write tostdout
instead of to a file by specifying a-
instead. Similarly, some tools would write tostdout
by default if you omit such an argument entirely (but this is not always possible without creating ambiguity). – Joost Sep 23 '16 at 14:06
pdfgrep was written for exactly this purpose and is available in Ubuntu.
It tries to be mostly compatible to grep
and thus provides "the power of grep", only specialized for PDFs. That includes common grep options, such as --recursive
, --ignore-case
or --color
.
In contrast to pdftotext | grep
, pdfgrep can output the page number of a match in a performant way and is generally faster when it doesn't have to search the whole document (e.g. --max-count
or --quiet
).
The basic usage is:
pdfgrep PATTERN FILE..
where PATTERN
is your search string and FILE
a list of filenames (or wildcards in a shell).
See the manpage for more infos.
No.
A pdf consists of chunks of data, some of them text, some of them pictures and some of them really magical fancy XYZ (eg. .u3d files). Those chunks are most of the times compressed (eg. flat, check http://www.verypdf.com/pdfinfoeditor/compression.htm). In order to 'grep' a .pdf you have to reverse the compression aka extract the text.
You can do that either per file with tools such as pdf2text
and grep the result, or you run an 'indexer' (look at xapian.org or lucene) which builds an searchable index out of your .pdf files and then you can use the search engine tools of that indexer to get the content of the pdf.
But no, you can not grep
pdf files and hope for reliable answers without extracting the text first.
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9Considering
pdfgrep
exists (see above), a flat "no" is incorrect. – Jonathan Cross Aug 28 '18 at 10:18 -
@JonathanCross, considering the question says "using the power of grep, without converting to text first", a flat "no" is correct. – Jivan Pal Nov 24 '20 at 8:58
Recoll can search PDFs. It doesn't support regular expressions, but it has lots of other search options, so it might fit your needs.
There is a duplicate question on StackOverflow. The people there suggest a variation of harish.venkarts answer:
find /path -name '*.pdf' -exec sh -c 'pdftotext "{}" - | grep --with-filename --label="{}" --color "your pattern"' \;
The advantage over the similar answer here is the --with-filename
flag for grep. This is somewhat superior to pdfgrep as well, because the standard grep has more features.
https://stackoverflow.com/questions/4643438/how-to-search-contents-of-multiple-pdf-files
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I think it would have been better to leave this as a comment (or edit) in the similar answer you are referring to. – Bernhard May 9 '14 at 12:07
Take a look at the common resource grep tool crgrep which supports searching within PDF files.
It also allows searching other resources like content nested in archives, database tables, image meta-data, POM file dependencies and web resources - and combinations of these including recursive search.
You could pipe it through strings
first:-
cat file.pdf | strings | grep <...etc...>
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9
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14
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6Even if the text is uncompressed, it's generally small pieces of sentences (not even necessarily whole words!) finely intermixed with formatting information. Not very friendly for
strings
orgrep
. – Jander Jan 31 '11 at 16:08 -
Can you think of another reason why using strings for this wouldn't work? I found that using strings works on some PDFs but not others. – hourback Nov 24 '15 at 19:58
try this
find /path -iname *.pdf -print0 | for i in `xargs 0`; do echo $i; \
pdftotext "$i" - | grep pattern; done
for printing the lines the pattern occurs inside the pdf
Here is a quick script for search pdf in the current directory :
#!/bin/bash
if [ $# -ne 1 ]; then
echo "usage $0 VALUE" 1>&2
exit 1
fi
echo 'SEARCH IS CASE SENSITIVE' 1>&2
find . -name '*.pdf' -exec /bin/bash -c 'pdftotext "{}" - | grep --with-filename --label="{}" --color "$0"' "$1" \;
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I cannot edit this due to being to little: The
$1
in the find invocation should be quoted, otherwise this won't work with search terms with spaces. – ankon Aug 25 '20 at 11:44 -
1
cd to your folder containing your pdf-file and then..
pdfgrep 'pattern' your.pdf
or if you want to search in more than just one pdf-file (e.g. in all pdf-files in your folder)
pdfgrep 'pattern' `ls *.pdf`
or
pdfgrep 'pattern' $(ls *.pdf)
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why on earth do you use ls to put filenames in parameters? It's not only slower but also a bad idea to use
ls
output as the input to other commands. Justpdfgrep 'pattern' *.pdf
is enough – phuclv Jan 31 '19 at 5:07 -
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@f0nzie you're wrong.
$(ls *.pdf)
will be almost exactly the same as*.pdf
, only worse because special files are not protected in quotes – phuclv Feb 26 '20 at 1:45
I assume you mean tp not convert it on the disk, you can convert them to stdout
and then grep it with pdftotext
. Grepping the pdf without any sort of conversion is not a practical approach since PDF
is mostly a binary format.
In the directory:
ls -1 ./*.pdf | xargs -L1 -I {} pdftotext {} - | grep "keyword"
or in the directory and its subdirectories:
tree -fai . | grep -P ".pdf$" | xargs -L1 -I {} pdftotext {} - | grep "keyword"
Also because some pdf
are scans they need to be OCRed first. I wrote a pretty simple way to search all pdfs that cannot be grep
ed and OCR them.
I noticed if a pdf
file doesn't have any font it is usually not searchable. So knowing this we can use pdffonts
.
First 2 lines of the pdffonts
are the table header, so when a file is searchable has more than two line output, knowing this we can create:
gedit check_pdf_searchable.sh
then paste this
#!/bin/bash
#set -vx
if ((`pdffonts "$1" | wc -l` < 3 )); then
echo $1
pypdfocr "$1"
fi
then make it executable
chmod +x check_pdf_searchable.sh
then list all non-searchable pdfs in the directory:
ls -1 ./*.pdf | xargs -L1 -I {} ./check_pdf_searchable.sh {}
or in the directory and its subdirectories:
tree -fai . | grep -P ".pdf$" | xargs -L1 -I {} ./check_pdf_searchable.sh {}
If you just want to search for pdf names/properties... or simple strings that are not compressed or encoded then instead of strings
you can use the below
grep -a STRING file.pdf
cat -v file.pdf | grep STRING
From grep --help
:
--binary-files=TYPE assume that binary files are TYPE;
TYPE is 'binary', 'text', or 'without-match'
-a, --text equivalent to --binary-files=text
and cat --help
:
-v, --show-nonprinting use ^ and M- notation, except for LFD and TAB
gpdf might be what you need if you're using Gnome! Check this in case you're not using Gnome. It's got a list of CLI pdf viewers. Then you can use grep
to find some pattern.
pdfgrep -r --include "*.pdf" -i 'pattern'
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3Welcome to the site, and thank you for your contribution. Could you add some explanation on what these options mean? This could also help explain how your approach differs from other answers to this question that also recommend
pdfgrep
. – AdminBee Aug 17 '20 at 9:53
Quickest way is
grep -rinw "pattern" --include \*.pdf *
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1Welcome to the site. Would you mind adding more explanation to your proposed solution to make it more accessible to the non-expert? For example, your
grep
command-line searches recursively in sub-directories which someone not familiar withgrep
might be unaware of. Also, you included the-i
flag although ignoring the case may not always be what the user wants. In addition, please explain in what way your approach differs from the asnwer of e.g. @phuclv and others. – AdminBee Jan 21 '20 at 8:12 -
1As AdminBee says, the question doesn’t ask for a case-insensitive search or a recursive directory search. The
-n
and-w
options aren’t justified by the question, either. But, more importantly, this answer tells how to search through text files whose names end with.pdf
— you’ve missed the point of the question. – G-Man Says 'Reinstate Monica' Jan 21 '20 at 8:22