Given an optionally quoted, pipe delimited file with the following records:
"foo"|"bar"|123|"9" Nails"|"2"
"blah"|"blah"|456|"Guns "N" Roses"|"7"
"brik"|"brak"|789|""BB" King"|"0"
"yin"|"yang"|789|"John "Cougar" Mellencamp"|"5"
I want to replace any double quotes not next to a delimiter.
I used the following and it almost works. With one exception.
sed "s/\([^|]\)\"\([^|]\)/\1'\2/g" a.txt
The output looks like this:
"foo"|"bar"|123|"9' Nails"|"2"
"blah"|"blah"|456|"Guns 'N" Roses"|"7"
"brik"|"brak"|789|"'BB' King"|"0"
"yin"|"yang"|789|"John 'Cougar' Mellencamp"|"5"
It doesn't catch the second set of quotes if they are separated by a single character as in Guns "N" Roses. Does anyone know why that is and how it can be fixed? In the mean time I'm just piping the output to a second regex to handle the special case. I'd prefer to do this in one pass since some of the files can be largish.
Thanks in advance.
You can use substitution twice in sed:
sed -r "s/([^|])\"([^|])/\1'\2/g; s/([^|])\"([^|])/\1'\2/g" file
"foo"|"bar"|123|"9' Nails"|"2"
"blah"|"blah"|456|"Guns 'N' Roses"|"7"
"brik"|"brak"|789|"'BB' King"|"0"
"yin"|"yang"|789|"John 'Cougar' Mellencamp"|"5"
sed kind of implements a "while" loop:
sed ':a; s/\([^|]\)"\([^|]\)/\1'\''\2/g; ta' file
The t command loops to the label a if the previous s/// command replaced something. So that will repeat the replacement until no other matches are found.
Also, perl handles your case without looping, thanks to zero-width look-ahead:
perl -pe 's/[^|]\K"(?!\||$)/'\''/g'
But it doesn't handle consecutive double quotes, so the loop:
perl -pe 's//'\''/g while /[^|]\K"(?!\||$)/' file
You may like to use \x27 instead of the awkward '\'' method to insert a single quote in a single quoted string. Works with perl and GNU sed.
Related
I'm trying to write a bash function that would escape all double quotes within single quotes, eg:
'I need to escape "these" quotes with backslashes'
would become
'I need to escape \"these\" quotes with backslashes'
My take on it was:
Find pairs of single quotes in the input and extract them with grep
Pipe into sed, escape double quotes
Sed again the whole input and replace grep match with sedded match
I managed to get it working to the part of having correctly escaped quotes section, but replacing it in the whole input fails.
The script code copypaste:
# $1 - Full name, $2 - minified name
adjust_quotes ()
{
SINGLE_QUOTES=`grep -Eo "'.*'" $2`
ESCAPED_QUOTES=`echo $SINGLE_QUOTES | sed 's|"|\\\\"|g'`
sed -r "s|'.*'|$ESCAPED_QUOTES|g" "$2" > "$2.escaped"
mv "$2.escaped" $2
echo "Quotes escaped within single quotes on $2"
}
Random additional questions:
In the console, escaping the quote with only two backslashes works, but when code is put in the script - I need four. I'd love to know
Could I modify this code into a loop to escape all pairs of single quotes, one after another until EOF?
Thanks!
P.S. I know this would probably be easier to do in eg. python, but I really need to keep it in bash.
Using BASH string replacement:
s='I need to escape "these" quotes with backslashes'
r="${s//\"/\\\"}"
echo "$r"
I need to escape \"these\" quotes with backslashes
Here's a pure bash solution, which does the transformation on stdin, printing to stdout. It reads the entire input into memory, so it won't work with really enormous files.
escape_enclosed_quotes() (
IFS=\'
read -d '' -r -a fields
for ((i=1; i<${#fields[#]}; i+=2)); do
fields[i]=${fields[i]//\"/\\\"}
done
printf %s "${fields[*]}"
)
I deliberately enclosed the body of the function in parentheses rather than braces, in order to force the body to run in a subshell. That limits the modification of IFS to the body, as well as implicitly making the variables used local.
The function uses the read builtin to read the entire input (since the line delimiter is set to NUL with -d '') into an array (-a) using a single quote as the field separator (IFS=\'). The result is that the parts of the input surrounded with single quotes are in the odd positions of the array, so the function loops over the odd indices to do the substitution only for those fields. I use bash's find-and-replace syntax instead of deferring to an external utility like sed.
This being bash, there are a couple of gotchas:
If the file contains a NUL, the rest of the file will be ignored.
If the last line of the file does not end with a newline, and the last character of that line is a single quote, it will not be output.
Both of the above conditions are impossible in a portable text file, so it's probably OK. All the same, worth taking note.
The supplementary question: why are the extra backslashes needed in
ESCAPED_QUOTES=`echo $SINGLE_QUOTES | sed 's|"|\\\\"|g'`
Answer: It has nothing to do with that line being in a script. It has to do with your use of backticks (...) for command substitution, and the idiosyncratic and often unpredictable handling of backslashes inside backticks. This syntax is deprecated. Do not use it. (Not even if you see someone else using it in some random example on the internet.) If you had used the recommended $(...) syntax for command substitution, it would have worked as expected:
ESCAPED_QUOTES=$(echo $SINGLE_QUOTES | sed 's|"|\\"|g')
(More information is in the Bash FAQ linked above.)
I have a ";" delimited file:
aa;;;;aa
rgg;;;;fdg
aff;sfg;;;fasg
sfaf;sdfas;;;
ASFGF;;;;fasg
QFA;DSGS;;DSFAG;fagf
I'd like to process it replacing the missing value with a \N .
The result should be:
aa;\N;\N;\N;aa
rgg;\N;\N;\N;fdg
aff;sfg;\N;\N;fasg
sfaf;sdfas;\N;\N;\N
ASFGF;\N;\N;\N;fasg
QFA;DSGS;\N;DSFAG;fagf
I'm trying to do it with a sed script:
sed "s/;\(;\)/;\\N\1/g" file1.txt >file2.txt
But what I get is
aa;\N;;\N;aa
rgg;\N;;\N;fdg
aff;sfg;\N;;fasg
sfaf;sdfas;\N;;
ASFGF;\N;;\N;fasg
QFA;DSGS;\N;DSFAG;fagf
You don't need to enclose the second semicolon in parentheses just to use it as \1 in the replacement string. You can use ; in the replacement string:
sed 's/;;/;\\N;/g'
As you noticed, when it finds a pair of semicolons it replaces it with the desired string then skips over it, not reading the second semicolon again and this makes it insert \N after every two semicolons.
A solution is to use positive lookaheads; the regex is /;(?=;)/ but sed doesn't support them.
But it's possible to solve the problem using sed in a simple manner: duplicate the search command; the first command replaces the odd appearances of ;; with ;\N, the second one takes care of the even appearances. The final result is the one you need.
The command is as simple as:
sed 's/;;/;\\N;/g;s/;;/;\\N;/g'
It duplicates the previous command and uses the ; between g and s to separe them. Alternatively you can use the -e command line option once for each search expression:
sed -e 's/;;/;\\N;/g' -e 's/;;/;\\N;/g'
Update:
The OP asks in a comment "What if my file have 100 columns?"
Let's try and see if it works:
$ echo "0;1;;2;;;3;;;;4;;;;;5;;;;;;6;;;;;;;" | sed 's/;;/;\\N;/g;s/;;/;\\N;/g'
0;1;\N;2;\N;\N;3;\N;\N;\N;4;\N;\N;\N;\N;5;\N;\N;\N;\N;\N;6;\N;\N;\N;\N;\N;\N;
Look, ma! It works!
:-)
Update #2
I ignored the fact that the question doesn't ask to replace ;; with something else but to replace the empty/missing values in a file that uses ; to separate the columns. Accordingly, my expression doesn't fix the missing value when it occurs at the beginning or at the end of the line.
As the OP kindly added in a comment, the complete sed command is:
sed 's/;;/;\\N;/g;s/;;/;\\N;/g;s/^;/\\N;/g;s/;$/;\\N/g'
or (for readability):
sed -e 's/;;/;\\N;/g;' -e 's/;;/;\\N;/g;' -e 's/^;/\\N;/g' -e 's/;$/;\\N/g'
The two additional steps replace ';' when they found it at beginning or at the end of line.
You can use this sed command with 2 s (substitute) commands:
sed 's/;;/;\\N;/g; s/;;/;\\N;/g;' file
aa;\N;\N;\N;aa
rgg;\N;\N;\N;fdg
aff;sfg;\N;\N;fasg
sfaf;sdfas;\N;\N;
ASFGF;\N;\N;\N;fasg
QFA;DSGS;\N;DSFAG;fagf
Or using lookarounds regex in a perl command:
perl -pe 's/(?<=;)(?=;)/\\N/g' file
aa;\N;\N;\N;aa
rgg;\N;\N;\N;fdg
aff;sfg;\N;\N;fasg
sfaf;sdfas;\N;\N;
ASFGF;\N;\N;\N;fasg
QFA;DSGS;\N;DSFAG;fagf
The main problem is that you can't use several times the same characters for a single replacement:
s/;;/..../g: The second ; can't be reused for the next match in a string like ;;;
If you want to do it with sed without to use a Perl-like regex mode, you can use a loop with the conditional command t:
sed ':a;s/;;/;\\N;/g;ta;' file
:a defines a label "a", ta go to this label only if something has been replaced.
For the ; at the end of the line (and to deal with eventual trailing whitespaces):
sed ':a;s/;;/;\\N;/g;ta; s/;[ \t\r]*$/;\\N/1' file
this awk one-liner will give you what you want:
awk -F';' -v OFS=';' '{for(i=1;i<=NF;i++)if($i=="")$i="\\N"}7' file
if you really want the line: sfaf;sdfas;\N;\N;\N , this line works for you:
awk -F';' -v OFS=';' '{for(i=1;i<=NF;i++)if($i=="")$i="\\N";sub(/;$/,";\\N")}7' file
sed 's/;/;\\N/g;s/;\\N\([^;]\)/;\1/g;s/;[[:blank:]]*$/;\\N/' YourFile
non recursive, onliner, posix compliant
Concept:
change all ;
put back unmatched one
add the special case of last ; with eventually space before the end of line
This might work for you (GNU sed):
sed -r ':;s/^(;)|(;);|(;)$/\2\3\\N\1\2/g;t' file
There are 4 senarios in which an empty field may occur: at the start of a record, between 2 field delimiters, an empty field following an empty field and at the end of a record. Alternation can be employed to cater for senarios 1,2 and 4 and senario 3 can be catered for by a second pass using a loop (:;...;t). Multiple senarios can be replaced in both passes using the g flag.
I want to change some names in a file using sed. This is how the file looks like:
#! /bin/bash
SAMPLE="sample_name"
FULLSAMPLE="full_sample_name"
...
Now I only want to change sample_name & not full_sample_name using sed
I tried this
sed s/\<sample_name\>/sample_01/g ...
I thought \<> could be used to find an exact match, but when I use this, nothing is changed.
Adding '' helped to only change the sample_name. However there is another problem now: my situation was a bit more complicated than explained above since my sed command is embedded in a loop:
while read SAMPLE
do
name=$SAMPLE
sed -e 's/\<sample_name\>/$SAMPLE/g' /path/coverage.sh > path/new_coverage.sh
done < $1
So sample_name should be changed with the value attached to $SAMPLE. However when running the command sample_name is changed to $SAMPLE and not to the value attached to $SAMPLE.
I believe \< and \> work with gnu sed, you just need to quote the sed command:
sed -i.bak 's/\<sample_name\>/sample_01/g' file
In GNU sed, the following command works:
sed 's/\<sample_name\>/sample_01/' file
The only difference here is that I've enclosed the command in single quotes. Even when it is not necessary to quote a sed command, I see very little disadvantage to doing so (and it helps avoid these kinds of problems).
Another way of achieving what you want more portably is by adding the quotes to the pattern and replacement:
sed 's/"sample_name"/"sample_01"/' script.sh
Alternatively, the syntax you have proposed also works in GNU awk:
awk '{sub(/\<sample_name\>/, "sample_01")}1' file
If you want to use a variable in the replacement string, you will have to use double quotes instead of single, for example:
sed "s/\<sample_name\>/$var/" file
Variables are not expanded within single quotes, which is why you are getting the the name of your variable rather than its contents.
#user1987607
You can do this the following way:
sed s/"sample_name">/sample_01/g
where having "sample_name" in quotes " " matches the exact string value.
/g is for global replacement.
If "sample_name" occurs like this ifsample_name and you want to replace that as well
then you should use the following:
sed s/"sample_name ">/"sample_01 "/g
So that it replaces only the desired word. For example the above syntax will replace word "the" from a text file and not from words like thereby.
If you are interested in replacing only first occurence, then this would work fine
sed s/"sample_name"/sample_01/
Hope it helps
$cat file0
"basic/strong/bold"
" /""?basic""/strong/bold"
"^/))basic"
basic
I want unix sed command such that only basic that is not in quotes should be changed.[change basic to ring]
Expected output:
$cat file0
"basic/strong/bold"
" /""?basic""/strong/bold"
"^/))basic"
ring
If we disallow escaping quotes, then any basic that is not within " is preceded by an even number of ". So this should do the trick:
sed -r 's/^([^"]*("[^"]*){2}*)basic/\1ring/' file
And as ДМИТРИЙ МАЛИКОВ mentioned, adding the --in-place option will immediately edit the file, instead of returning the new contents.
How does this work?
We anchor the regular expression to the beginning of each line with ". Then we allow an arbitrary number of non-" characters (with [^"]*). Then we start a new subpattern "[^"]* that consists of one " and arbitrarily many non-" characters. We repeat that an even number of times (with {2}*). And then we match basic. Because we matched all of that stuff in the line before basic we would replace that as well. That's why this part is wrapped in another pair of parentheses, thus capturing the line and writing it back in the replacement with \1 followed by ring.
One caveat: if you have multiple basic occurrences in one line, this will only replace the last one that is not enclosed in double quotes, because regex matches cannot overlap. A solution would be a lookbehind, but since this would be a variable-length lookbehind, which is only supported by the .NET regex engine. So if that is the case in your actual input, run the command multiple times until all occurrences are replaced.
$> sed -r 's/^([^\"]*)(basic)([^\"]*)$/\1ring\3/' file0
"basic/strong/bold"
" /""?basic""/strong/bold"
"^/))basic"
ring
If you wanna edit file in place use --in-place option.
This might work for you (GNU sed):
sed -r 's/^/\n/;ta;:a;s/\n$//;t;s/\n("[^"]*")/\1\n/;ta;s/\nbasic/ring\n/;ta;s/\n([^"]*)/\1\n/;ta' file
Not a sed solution, but it substitutes words not in quotes
Assuming that there is no escaped quotes in strings, i.e. "This is a trap \" hehe", awk might be able to solve this problem
awk -F\" 'BEGIN {OFS=FS}
{
for(i=1; i<=NF; i++){
if(i%2)
gsub(/basic/,"ring",$i)
}
print
}' inputFile
Basically the words that are not in quotes are in odd-numbered fields, and the word "basic" is replaced by "ring" in these fields.
This can be written as a one-liner, but for clarity's sake I've written it in multiple lines.
If basic is at the beginning of line:
sed -e 's/^basic/ring/' file0
I have a file that looks like this:
#"Afghanistan.png",
#"Albania.png",
#"Algeria.png",
#"American_Samoa.png",
I want it to look like this
#"Afghanistan.png",
#"Afghanistan",
#"Albania.png",
#"Albania",
#"Algeria.png",
#"Algeria",
#"American_Samoa.png",
#"American_Samoa",
I thought I could use sed to do this but I can't figure out how to store something in a buffer and then modify it.
Am I even using the right tool?
Thanks
You don't have to get tricky with regular expressions and replacement strings: use sed's p command to print the line intact, then modify the line and let it print implicitly
sed 'p; s/\.png//'
Glenn jackman's response is OK, but it also doubles the rows which do not match the expression.
This one, instead, doubles only the rows which matched the expression:
sed -n 'p; s/\.png//p'
Here, -n stands for "print nothing unless explicitely printed", and the p in s/\.png//p forces the print if substitution was done, but does not force it otherwise
That is pretty easy to do with sed and you not even need to use the hold space (the sed auxiliary buffer). Given the input file below:
$ cat input
#"Afghanistan.png",
#"Albania.png",
#"Algeria.png",
#"American_Samoa.png",
you should use this command:
sed 's/#"\([^.]*\)\.png",/&\
#"\1",/' input
The result:
$ sed 's/#"\([^.]*\)\.png",/&\
#"\1",/' input
#"Afghanistan.png",
#"Afghanistan",
#"Albania.png",
#"Albania",
#"Algeria.png",
#"Algeria",
#"American_Samoa.png",
#"American_Samoa",
This commands is just a replacement command (s///). It matches anything starting with #" followed by non-period chars ([^.]*) and then by .png",. Also, it matches all non-period chars before .png", using the group brackets \( and \), so we can get what was matched by this group. So, this is the to-be-replaced regular expression:
#"\([^.]*\)\.png",
So follows the replacement part of the command. The & command just inserts everything that was matched by #"\([^.]*\)\.png", in the changed content. If it was the only element of the replacement part, nothing would be changed in the output. However, following the & there is a newline character - represented by the backslash \ followed by an actual newline - and in the new line we add the #" string followed by the content of the first group (\1) and then the string ",.
This is just a brief explanation of the command. Hope this helps. Also, note that you can use the \n string to represent newlines in some versions of sed (such as GNU sed). It would render a more concise and readable command:
sed 's/#"\([^.]*\)\.png",/&\n#"\1",/' input
I prefer this over Carles Sala and Glenn Jackman's:
sed '/.png/p;s/.png//'
Could just say it's personal preference.
or one can combine both versions and apply the duplication only on lines matching the required pattern
sed -e '/^#".*\.png",/{p;s/\.png//;}' input