I'm looking for a way to search and replace over multiple lines through a shell script. This is what I'm trying to do:
source:
[stuff before]
<!--WIERD_SPECIAL_COMMENT_BEGIN-->
[stuff here, possibly multiple lines.
<!--WIERD_SPECIAL_COMMENT_END-->
[stuff after]
target:
[stuff before]
[new content]
[stuff after]
In short, I want to delete the comments and everything between them and replace with some new content. Basically, I want to do a simple sed command over multiple lines, and if possible just using some basic *nix tools, no additional scripting language.
If you only need to match complete lines then you can do this task with
awk. Something like:
awk -v NEWTEXT=foo 'BEGIN{n=0} /COMMENT_BEGIN/ {n=1} {if (n==0) {print $0}} /COMMENT_END/ {print NEWTEXT; n=0}' < myfile.txt
If the file is not so well formatted, with comments on
the same line as text you want to keep or remove, then I
would use perl, read the entire file into a single string,
do a regular expression match and replace on that string, then write the new string to
a new file. This is not so simple and you need to write a perl script to do the work.
Something like:
#!/usr/bin/perl
$newtext = "foo\nbar";
$/ = ''; # no input separator so whole file is read.
$s = <>; # read whole file from stdin
$startPattern = quotemeta('<!--WIERD_SPECIAL_COMMENT_BEGIN-->');
$endPattern = quotemeta('<!--WIERD_SPECIAL_COMMENT_END-->');
$pattern = $startPattern . '.+' . $endPattern;
$s =~ s/$pattern/$newtext/sg;
print $s;
sed does this just fine. The following is as simple as it gets; if you need to extract stuff from the delimiter line before the start delimiter or after the end delimiter, that's going to be a little more complex.
sed '/<!--WIERD_SPECIAL_COMMENT_BEGIN-->/,/<!--WIERD_SPECIAL_COMMENT_END-->/d' input >output
If you have any control over this, fix the spelling of "weird".
another solution... this is possible to be done in a one-liner, but using perl regular expressions, which I find easier to work with than sed or awk (which are cumbersome with multi-line match and replace):
perl -0 -i -pe 's/<!--WIERD_SPECIAL_COMMENT_BEGIN-->[\s\S]*<!--WIERD_SPECIAL_COMMENT_END-->/your new content here/gim' yourfile1.txt
please note that this will replace the file with the new, changed content.
Related
I'm attempting to convert my personal wiki from Foswiki to Markdown files and then to a JAMstack deployment. Foswiki uses flat files and stores metadata in the following format:
%META:TOPICINFO{author="TeotiNathaniel" comment="reprev" date="1571215308" format="1.1" reprev="13" version="14"}%
I want to use a git repo for versioning and will worry about linking that to article metatada later. At this point I simply want to convert these blocks to something that looks like this:
---
author: Teoti Nathaniel
revdate: 1539108277
---
After a bit of tweaking I have constructed the following regex:
author\=\['"\]\(\\w\+\)\['"\]\(\?\:\.\*\)date\=\['"\]\(\\w\+\)\['"\]
According to regex101 this works and my two capture groups contain the desired results. Attempting to actually run it:
perl -0777 -pe 's/author\=\['"\]\(\\w\+\)\['"\]\(\?\:\.\*\)date\=\['"\]\(\\w\+\)\['"\]/author: $1\nrevdate: $2/gms' somefile.txt
gets me only this:
>
My previous attempt (which breaks if the details aren't in a specific order) looked like this and executed correctly:
perl -0777 -pe 's/%META:TOPICINFO\{author="(.*)"\ date="(.*)"\ format="(.*)"\ (.*)\}\%/author:$1 \nrevdate:$2/gms' somefile.txt
I think that this is an escape character problem but can't figure it out. I even went and found this tool to make sure that they are correct.
Brute-forcing my way to understanding here is feeling both inefficient and frustrating, so I'm asking the community for help.
The first major problem is that you're trying to use a single quote (') in the program, when the program is being passed to the shell in single quotes.
Escape any instance of ' in the program by using '\''. You could also use \x27 if the quote happens to be a single double-quoted string literal or regex literal (as is the case of every instance in your program).
perl -0777pe's/author=['\''"].../.../gs'
perl -0777pe's/author=[\x27"].../.../gs'
I would try to break it down into a clean data structure then process it. By seperating the data processing to printing, you can modifiy to add extra data later. It also makes it far more readable. Please see the example below
#!/usr/bin/env perl
use strict;
use warnings;
## yaml to print the data, not required for operation
use YAML::XS qw(Dump);
my $yaml;
my #lines = '%META:TOPICINFO{author="TeotiNathaniel" comment="reprev" date="1571215308" format="1.1" reprev="13" version="14"}%';
for my $str (#lines )
{
### split line into component parts
my ( $type , $subject , $data ) = $str =~ /\%(.*?):(.*?)\{(.*)\}\%/;
## break data in {} into a hash
my %info = map( split(/=/), split(/\s+/, $data) );
## strip quotes if any exist
s/^"(.*)"$/$1/ for values %info;
#add to data structure
$yaml->{$type}{$subject} = \%info;
}
## yaml to print the data, not required for operation
print Dump($yaml);
## loop data and print
for my $t (keys %{ $yaml } ) {
for my $s (keys %{ $yaml->{$t} } ) {
print "-----------\n";
print "author: ".$yaml->{$t}{$s}{"author"}."\n";
print "date: ".$yaml->{$t}{$s}{"date"}."\n";
}
}
Ok, I kept fooling around with it by reducing the execution to a single term and expanding. I soon got to here:
$ perl -0777 -pe 's/author=['\"]\(\\w\+\)['"](?:.*)date=\['\"\]\(\\w\+\)\['\"\]/author\: \$1\\nrevdate\: \$2/gms' somefile.txt
Unmatched [ in regex; marked by <-- HERE in m/author=["](\w+)["](?:.*)date=\["](\w+)[ <-- HERE \"\]/ at -e line 1.
This eventually got me to here:
perl -0777 -pe 's/author=['\"]\(\\w\+\)['"](?:.*)date=['\"]\(\\w\+\)['\"]/\nauthor\ $1\nrevdate\:$2\n/gms' somefile.txt
Which produces a messy output but works. (Note: Output is proof-of-concept and this can now be used within a Python script to programattically generate Markdown metadata.
Thanks for being my rubber duckie, StackOverflow. Hopefully this is useful to someone, somewhere, somewhen.
I have a very large file, containing the following blocks of lines throughout:
start :234
modify 123 directory1/directory2/file.txt
delete directory3/file2.txt
modify 899 directory4/file3.txt
Each block starts with the pattern "start : #" and ends with a blank line. Within the block, every line starts with "modify # " or "delete ".
I need to modify the path in each line, specifically appending a directory to the front. I would just use a general regex to cover the entire file for "modify #" or "delete ", but due to the enormous amount of other data in that file, there will likely be other matches to this somewhat vague pattern. So I need to use multi-line matching to find the entire block, and then perform edits within that block. This will likely result in >10,000 modifications in a single pass, so I'm also trying to keep the execution down to less than 30 minutes.
My current attempt is a sed one-liner:
sed '/^start :[0-9]\+$/ { :a /^[modify|delete] .*$/ { N; ba }; s/modify [0-9]\+ /&Appended_DIR\//g; s/delete /&Appended_DIR\//g }' file_to_edit
Which is intended to find the "start" line, loop while the lines either start with a "modify" or a "delete," and then apply the sed replacements.
However, when I execute this command, no changes are made, and the output is the same as the original file.
Is there an issue with the command I have formed? Would this be easier/more efficient to do in perl? Any help would be greatly appreciated, and I will clarify where I can.
I think you would be better off with perl
Specifically because you can work 'per record' by setting $/ - if you're records are delimited by blank lines, setting it to \n\n.
Something like this:
#!/usr/bin/env perl
use strict;
use warnings;
local $/ = "\n\n";
while (<>) {
#multi-lines of text one at a time here.
if (m/^start :\d+/) {
s/(modify \d+)/$1 Appended_DIR\//g;
s/(delete) /$1 Appended_DIR\//g;
}
print;
}
Each iteration of the loop will pick out a blank line delimited chunk, check if it starts with a pattern, and if it does, apply some transforms.
It'll take data from STDIN via a pipe, or myscript.pl somefile.
Output is to STDOUT and you can redirect that in the normal way.
Your limiting factor on processing files in this way are typically:
Data transfer from disk
pattern complexity
The more complex a pattern, and especially if it has variable matching going on, the more backtracking the regex engine has to do, which can get expensive. Your transforms are simple, so packaging them doesn't make very much difference, and your limiting factor will be likely disk IO.
(If you want to do an in place edit, you can with this approach)
If - as noted - you can't rely on a record separator, then what you can use instead is perls range operator (other answers already do this, I'm just expanding it out a bit:
#!/usr/bin/env perl
use strict;
use warnings;
while (<>) {
if ( /^start :/ .. /^$/)
s/(modify \d+)/$1 Appended_DIR\//g;
s/(delete) /$1 Appended_DIR\//g;
}
print;
}
We don't change $/ any more, and so it remains on it's default of 'each line'. What we add though is a range operator that tests "am I currently within these two regular expressions" that's toggled true when you hit a "start" and false when you hit a blank line (assuming that's where you would want to stop?).
It applies the pattern transformation if this condition is true, and it ... ignores and carries on printing if it is not.
sed's pattern ranges are your friend here:
sed -r '/^start :[0-9]+$/,/^$/ s/^(delete |modify [0-9]+ )/&prepended_dir\//' filename
The core of this trick is /^start :[0-9]+$/,/^$/, which is to be read as a condition under which the s command that follows it is executed. The condition is true if sed currently finds itself in a range of lines of which the first matches the opening pattern ^start:[0-9]+$ and the last matches the closing pattern ^$ (an empty line). -r is for extended regex syntax (-E for old BSD seds), which makes the regex more pleasant to write.
I would also suggest using perl. Although I would try to keep it in one-liner form:
perl -i -pe 'if ( /^start :/ .. /^$/){s/(modify [0-9]+ )/$1Append_DIR\//;s/(delete )/$1Append_DIR\//; }' file_to_edit
Or you can use redirection of stdout:
perl -pe 'if ( /^start :/ .. /^$/){s/(modify [0-9]+ )/$1Append_DIR\//;s/(delete )/$1Append_DIR\//; }' file_to_edit > new_file
with gnu sed (with BRE syntax):
sed '/^start :[0-9][0-9]*$/{:a;n;/./{s/^\(modify [0-9][0-9]* \|delete \)/\1NewDir\//;ba}}' file.txt
The approach here is not to store the whole block and to proceed to the replacements. Here, when the start of the block is found the next line is loaded in pattern space, if the line is not empty, replacements are performed and the next line is loaded, etc. until the end of the block.
Note: gnu sed has the alternation feature | available, it may not be the case for some other sed versions.
a way with awk:
awk '/^start :[0-9]+$/,/^$/{if ($1=="modify"){$3="newdirMod/"$3;} else if ($1=="delete"){$2="newdirDel/"$2};}{print}' file.txt
This is very simple in Perl, and probably much faster than the sed equivalent
This one-line program inserts Appended_DIR/ after any occurrence of modify 999 or delete at the start of a line. It uses the range operator to restrict those changes to blocks of text starting with start :999 and ending with a line containing no printable characters
perl -pe"s<^(?:modify\s+\d+|delete)\s+\K><Appended_DIR/> if /^start\s+:\d+$/ .. not /\S/" file_to_edit
Good grief. sed is for simple substitutions on individual lines, that is all. Once you start using constructs other than s, g, and p (with -n) you are using the wrong tool. Just use awk:
awk '
/^start :[0-9]+$/ { inBlock=1 }
inBlock { sub(/^(modify [0-9]+|delete) /,"&Appended_DIR/") }
/^$/ { inBlock=0 }
{ print }
' file
start :234
modify 123 Appended_DIR/directory1/directory2/file.txt
delete Appended_DIR/directory3/file2.txt
modify 899 Appended_DIR/directory4/file3.txt
There's various ways you can do the above in awk but I wrote it in the above style for clarity over brevity since I assume you aren't familiar with awk but should have no trouble following that since it reuses your own sed scripts regexps and replacement text.
OCR texts often have words that flow from one line to another with a hyphen at the end of the first line. (ie: the word has '-\n' inserted in it).
I would like rejoin all such split words in a text file (in a linux environment).
I believe this should be possible with sed or awk, but the syntax for these is dark magic to me! I knew a text editor in windows that did regex search/replace with newlines in the search expression, but am unaware of such in linux.
Make sure to back up ocr_file before running as this command will modify the contents of ocr_file:
perl -i~ -e 'BEGIN{$/=undef} ($f=<>) =~ s#-\s*\n\s*(\S+)#$1\n#mg; print $f' ocr_file
This answer is relevant, because I want the words joined together... not just a removal of the dash character.
cat file| perl -CS -pe's/-\n//'|fmt -w52
is the short answer, but uses fmt to reform paragraphs after the paragraphs were mangled by perl.
without fmt, you can do
#!/usr/bin/perl
use open qw(:std :utf8);
undef $/; $_=<>;
s/-\n(\w+\W+)\s*/$1\n/sg;
print;
also, if you're doing OCR, you can use this perl one-liner to convert unicode utf-8 dashes to ascii dash characters. note the -CS option to tell perl about utf-8.
# 0x2009 - 0x2015 em-dashes to ascii dash
perl -CS -pe 'tr/\x{2009}\x{2010}\x{2011}\x{2012\x{2013}\x{2014}\x{2015}/-/'
cat file | perl -p -e 's/-\n//'
If the file has windows line endings, you'll need to catch the cr-lf with something like:
cat file | perl -p -e 's/-\s\n//'
Hey this is my first answer post, here goes:
'-\n' I suspect are the line-feed characters. You can use sed to remove these. You could try the following as a test:
1) create a test file:
echo "hello this is a test -\n" > testfile
2) check the file has the expected contents:
cat testfile
3) test the sed command, this sends the edited text stream to standard out (ie your active console window) without overwriting anything:
sed 's/-\\n//g' testfile
(you should just see 'hello this is a test file' printed to the console without the '-\n')
If I build up the command:
a) First off you have the sed command itself:
sed
b) Secondly the expression and sed specific controls need to be in quotations:
sed 'sedcontrols+regex' (the text in quotations isn't what you'll actually enter, we'll fill this in as we go along)
c) Specify the file you are reading from:
sed 'sedcontrols+regex' testfile
d) To delete the string in question, sed needs to be told to substitute the unwanted characters with nothing (null,zero), so you use 's' to substitute, forward-slash, then the unwanted string (more on that in a sec), then forward-slash again, then nothing (what it's being substituted with), then forward-slash, and then the scale (as in do you want to apply the edit to a single line or more). In this case I will select 'g' which represents global, as in the whole text file. So now we have:
sed 's/regex//g' testfile
e) We need to add in the unwanted string but it gets confusing because if there is a slash in your string, it needs to be escaped out using a back-slash. So, the unwanted string
-\n ends up looking like -\\n
We can output the edited text stream to stdout as follows:
sed 's/-\\n//g' testfile
To save the results without overwriting anything (assuming testfile2 doesn't exist) we can redirect the output to a file:
sed 's/-\\n//g' testfile >testfile2
sed -z 's/-\n//' file_with_hyphens
I have a large number of csv files that look like this below:
xxxxxxxx
xxxxx
Shipment,YD564n
xxxxxxxxx
xxxxx
1,RR1760
2,HI3503
3,HI4084
4,HI1824
I need to make them look like the following:
xxxxxxxx
xxxxx
Shipment,YD564n
xxxxxxxxx
xxxxx
YD564n,1,RR1760
YD564n,2,HI3503
YD564n,3,HI4084
YD564n,4,HI1824
YD564n is a shipment number and will be different for every csv file. But it always comes right after "Shipment,".
What vim command(s) can I use?
In one file type the following in normal mode:
qqgg/^Shipment,<CR>ww"ay$}j:.,$s/^/<C-R>a,<CR>q
Note that <CR> is the ENTER key, and <C-R> is CTRL-R.
This will update that file and recrd the commands in register q.
Then in each other file type #q (also in normal mode). (this will play back register q)
You can do this using a macro, and applying it over several files.
Here's one example. Type the following in as is:
3gg$"ayiw:6,$s/^/<C-R>a/<CR>:w<CR>:bn<CR>
Now that looks horrendous. Let me see if I can explain that a bit better.
3gg$ : Go to the end of the third line.
"ayiw : Copy the last word into the register a.
:6,$s/^/<C-R>a/<CR> : In every line from the 6th onwards, replace at the beginning whatever is in register a.
:w<CR>:bn<CR> : Save and go to the next buffer.
Now you can map this to a key, by
:nnoremap <C-A> 3gg$"ayiw:6,$s/^/<C-R>a/<CR>:w<CR>:bn<CR>
Then if you have say 200 csv files, you open vim as
vim *.csv
and then
200<C-A>
Where you type Ctrl-A there, and it should be all done.
That said, I'd definitely be more comfortable doing this in a proper scripting language, it'd be much more straightforward.
This could be done as a Perl one-liner:
perl -i.bak -e' $c = do {local $/; <>};
($n) = ($c =~ /Shipment,(\w+)/);
$c =~ s/^(\d+,)/$n,$1/gm;
print $c' shipment.csv
This will read contents of shipment.csv into $c, extract the shipment ID into $n, and prepend every CSV line with the shipment number. The file will be modified in-place with a backup saved to shipment.csv.bak.
To do this from within Vim, adapt it as a filter:
:%!perl -e' $c = do {local $/; <>}; ($n) = ($c =~ /Shipment,(\w+)/); $c =~ s/^(\d+,)/$n,$1/gm; print $c'
Well, don't bash me, but... you could consider: Don't do this in vim!!
This is a classic usage example for scripting languages.
Take a basic python, perl or ruby tutorial. The solution for this would
be in it.
The regex for this might not be too difficult and it is doable in vim.
But there are much easier alternatives out there.
And much more flexible ones.
Why vim?
Try this shell script:
#!/bin/sh
input=$1
shipment=`grep Shipment $input|awk -F, '{print $2}'`
mv $input $input.orig
sed -e "s/^\([0-9]\)/$shipment,\1/" $input.orig > $input
You could iterate through specific files:
for input in *.txt
do
script.sh $i
done
I also think this isn't well suited for vim, how about in Bash instead?
FILENAME='filename.csv' && SHIPMENT=`grep Shipment $FILENAME | sed 's/^Shipment,//'` && cat $FILENAME | sed "s/^[0-9]/$SHIPMENT,&/" > $FILENAME
I am attempting to write a one-line Perl script that will toggle a line in a configuration file from "commented" to not and back. I have the following so far:
perl -pi -e 's/^(#?)(\tDefaultServerLayout)/ ... /e' xorg.conf
I am trying to figure out what code to put in the replacement (...) section. I would like the replacement to insert a '#' if one was not matched on, and remove it if it was matched on.
pseudo code:
if ( $1 == '#' ) then
print $2
else
print "#$2"
My Perl is very rusty, and I don't know how to fit that into a s///e replacement.
My reason for this is to create a single script that will change (toggle) my display settings between two layouts. I would prefer to have this done in only one script.
I am open to suggestions for alternate methods, but I would like to keep this a one-liner that I can just include in a shell script that is doing other things I want to happen when I change layouts.
perl -pi -e 's/^(#?)(?=\tDefaultServerLayout)/ ! $1 && "#" /e' foo
Note the addition of ?= to simplify the replacement string by using a look-ahead assertion.
Some might prefer s/.../ $1 ? "" : "#" /e.