I've been searching google for ever, and I cannot find an example of how to do this. I also do not grasp the concept of how to construct a regular expression for SED, so I was hoping someone could explain this to me.
I'm running a bash script against a file full of lines of text that look like this: 2222,H,73.82,04,07,2012
and I need to make them all look like this: 2222,H,73.82,04072012
I need to remove the last two commas, which are the 16th and 19th characters in the line.
Can someone tell me how to do that? I was going to use colrm, which is blessedly simple, but i can't seem to get that installed in CYGWIN. Please and thank you!
I'd use awk for this:
awk -F',' -v OFS=',' '{ print $1, $2, $3, $4$5$6 }' inputfile
This takes a CSV file and prints the first, second and third fields, each followed by the output field separator (",") and then the fourth, fifth and sixth fields concatenated.
Personally I find this easier to read and maintain than regular expression-based solutions in sed and it will cope well if any of your columns get wider (or narrower!).
This will work on any string and will remove only the last 2 commas:
sed -e 's/\(.*\),\([^,]*\),\([^,]*\)$/\1\2\3/' infile.txt
Note that in my sed variant I have to escape parenthesis, YMMV.
I also do not grasp the concept of how to construct a regular
expression for SED, so I was hoping someone could explain this to me.
The basic notation that people are telling you here is: s/PATTERN/REPLACEMENT/
Your PATTERN is a regular expression, which may contain parts that are in brackets. Those parts can then be referred to in the REPLACEMENT part of the command. For example:
> echo "aabbcc" | sed 's/\(..\)\(..\)\(..\)/\2\3\1/'
bbccaa
Note that in the version of sed I'm using defaults to the "basic" RE dialect, where the brackets in expressions need to be escaped. You can do the same thing in the "extended" dialect:
> echo "aabbcc" | sed -E 's/(..)(..)(..)/\2\3\1/'
bbccaa
(In GNU sed (which you'd find in Linux), you can get the same results with the -r options instead of -E. I'm using OS X.)
I should say that for your task, I would definitely follow Johnsyweb's advice and use awk instead of sed. Much easier to understand. :)
It should work :
sed -e 's~,~~4g' file.txt
remove 4th and next commas
echo "2222,H,73.82,04,07,2012" | sed -r 's/(.{15}).(..)./\1\2/'
Take 15 chars, drop one, take 2, drop one.
sed -e 's/(..),(..),(....)$/\1\2\3/' myfile.txt
Related
I have a text file that is basically one giant excel file on one line in a text file. An example would be like this:
Name,Age,Year,Michael,27,2018,Carl,19,2018
I need to change the third occurance of a comma into a new line so that I get
Name,Age,Year
Michael,27,2018
Carl,19,2018
Please let me know if that is too ambiguous and as always thank you in advance for all the help!
With Gnu sed:
sed -E 's/(([^,]*,){2}[^,]*),/\1\n/g'
To change the number of fields per line, change {2} to one less than the number of fields. For example, to change every fifth comma (as in the title of your question), you would use:
sed -E 's/(([^,]*,){4}[^,]*),/\1\n/g'
In the regular expression, [^,]*, is "zero or more characters other than , followed by a ,; in other words, it is a single comma-delimited field. This won't work if the fields are quoted strings with internal commas or newlines.
Regardless of what Linux's man sed says, the -E flag is an extension to Posix sed, which causes sed to use extended regular expressions (EREs) rather than basic regular expressions (see man 7 regex). -E also works on BSD sed, used by default on Mac OS X. (Thanks to #EdMorton for the note.)
With GNU awk for multi-char RS:
$ awk -v RS='[,\n]' '{ORS=(NR%3 ? "," : "\n")} 1' file
Name,Age,Year
Michael,27,2018
Carl,19,2018
With any awk:
$ awk -v RS=',' '{sub(/\n$/,""); ORS=(NR%3 ? "," : "\n")} 1' file
Name,Age,Year
Michael,27,2018
Carl,19,2018
Try this:
$ cat /tmp/22.txt
Name,Age,Year,Michael,27,2018,Carl,19,2018,Nooka,35,1945,Name1,11,19811
$ echo "Name,Age,Year"; grep -o "[a-zA-Z][a-zA-Z0-9]*,[1-9][0-9]*,[1-9][0-9]\{3\}" /tmp/22.txt
Michael,27,2018
Carl,19,2018
Nooka,35,1945
Name1,11,1981
Or, ,[1-9][0-9]\{3\} if you don't want to put [0-9] 3 more times for the YYYY part.
PS: This solution will give you only YYYY for the year (even if the data for YYYY is 19811 (typo mistakes if any), you'll still get 1981
You are looking for 3 fragments, each without a comma and separated by a comma.
The last fields can give problems (not ending with a comma and mayby only two fields.
The next command looks fine.
grep -Eo "([^,]*[,]{0,1}){0,3}" inputfile
This might work for you (GNU sed):
sed 's/,/\n/3;P;D' file
Replace every third , with a newline, print ,delete the first line and repeat.
how to tell awk ignore the delmiter in double quotation marks
eg
line='test,t2,t3,"t5,"'
$(echo $line | awk -F "," '{print $4}')
Expected value is "t5,"
but in fact is "t5"
how to get "t5,"?
With GNU awk for FPAT, all you need for your case is:
$ line='test,t2,t3,"t5,"'
$ echo "$line" | awk -v FPAT='([^,]*)|("[^"]*")' '{print $4}'
"t5,"
and if your awk can contain newlines and escaped quotes then see What's the most robust way to efficiently parse CSV using awk?.
Your arbitrary input could be checked or if you know where your input is not well formatted, use substr() starting from index 2 in column 4.
$ echo 'test,t2,t3,"t5,"' | awk -F, '{printf "%s,\n", substr($4,2) }'
t5,
Perhaps this is better.
echo 'test,t2,t3,"t5,"' | awk -F, '{print $(NF-1),$NF}' OFS=,
"t5,"
In the general case, you can't. You need a full parser to remember a tag, change state, then go back to the prior state when it encounters the matching tag. You can't do it with a regular expression unless you make a lot of assumptions about the shape of your data--and since I see you're parsing CSV, those assumptions will not hold true.
If you like awk, I suggest trying perl for this problem. You can either use somebody else's CSV parsing library (search here), or you can write your own. Of course, there's no reason you can't write a CSV parser in pure awk, so long as you understand that this is not what awk is good at. You need to parse character by character (don't separate records by newlines), remember the current state (is the line quoted?) and remember the previous character to see whether it was a backslash (for treating a quote as a literal quote or a comma as a literal comma). You need to remember the previous quote so you can parse "" as an escaped quote instead of a malformed field. It's kind of fun, and it's a bitch. Use somebody else's library if you like. I wouldn't choose awk to write any parser where the records don't have an obvious separator.
Edit: Ed Morton actually did write a full CSV parser for Gawk, which he linked to in his answer. I helped him break it, and he quickly fixed the problem case. His script will be useful, though it will be somewhat unwieldy to adapt to real-world uses.
I'm trying to do this with sed
sed -i.bak 's,[href="#">bebeco.fr],href="http://www.bebeco.fr,http://mm.eulerian.net/dynclick/bebeco/?eml-publisher=bebeco&eml-name=deme_faible&eemail={email}&eurl=https://www.bebeco.fr/?utm_source=ANIM&utm_medium=Targeting&utm_campaign=deme_faible&utm_term=CCCC_seg_men&utm_content=website">bebeco.fr,g' pour_test_demenagement-lien-faible.html
As you can imagine, due to the multiple meta characters, the sed command line is bugging and not changing the line.
What can I do to solve the problem and not put a \ before each metacharacter?
Do you think awkcan help, without going into programming?
TIA
You are falling into the trap of thinking sed can operate on strings. It cannot. It operates on regexps with additional "special" characters. Just use awk as it does support string operations. Here's how to replace an old string with a new string:
awk -v old="original" -v new="replacement" 's=index($0,old){$0=substr($0,1,s-1) new substr($0,s+length(old))}1' file
It would be great if sed had a way to support strings like grep does with -F but it doesn't. It'd also be great if there was a briefer way to write it in awk but there isn't. So let's just suck it up and do string operations as provided by the tool that supports them instead of trying to find "special" characters that will sometimes work as delimiters and cobble together escape sequences to try to disable regexp metacharacters.
I would simply use a different separator. What about good old ~? The data as shown does not contain the ~:
sed 's~SEARCH~REPLACE~'
Do you think awk can help, without going into programming?
:) Since awk is a programming language, I don't think it is possible without going into programming. However, I think sed is ok for that job.
Your regex syntax is hosed. [href="#">bebeco.fr] matches a single character which is one of h, r, e, etc. On top of that, you have three fields where sed only permits two, so it's not clear what you are trying to accomplish; but perhaps something like
sed -i.bak 's,href="#">bebeco.fr,href="http://mm.eulerian.net/dynclick/bebeco/?eml-publisher=bebeco\&eml-name=deme_faible\&eemail={email}\&eurl=https://www.bebeco.fr/?utm_source=ANIM\&utm_medium=Targeting\&utm_campaign=deme_faible\&utm_term=CCCC_seg_men\&utm_content=website">bebeco.fr,g' pour_test_demenagement-lien-faible.html
That is, replace the hash in the double-quoted string in href="#">bebeco.fr with a long URL.
You can try to create and escaped pattern
MyStringSearch='ref="#">bebeco.fr'
MyStringSearchEsc="$( printf '%s' "${MyStringSearch}" | sed 's#\[]["\&*.\\/+?]#\\&#g' )"
MyStringReplace='href="http://mm.eulerian.net/dynclick/bebeco/?eml-publisher=bebeco\&eml-name=deme_faible\&eemail={email}\&eurl=https://www.bebeco.fr/?utm_source=ANIM\&utm_medium=Targeting\&utm_campaign=deme_faible\&utm_term=CCCC_seg_men\&utm_content=website">bebeco.fr'
MyStringReplaceEsc="$( printf '%s' "${MyStringReplace}" | sed 's#\[\\/\&"]#\\&#g' )"
before us it in final sed.
sed "s/${MyStringSearchEsc}/${MyStringReplaceEsc}/g" pour_test_demenagement-lien-faible.html
I've got a the following variable LINES with the format date;album;song;duration;singer;author;genre.
August 2013;MDNA;Falling Free;00:31:40;Madonna;Madonna;Pop
August 2013;MDNA;I don't give a;00:45:40;Madonna;Madonna;Pop
August 2013;MDNA;I'm a sinner;01:00:29;Madonna;Madonna;Pop
August 2013;MDNA;Give Me All Your Luvin';01:15:02;Madonna;Madonna;Pop
I want to output author-song, so I made this script:
echo $LINES | sed s_"^[^;]*;[^;]*;\([^;]*\);[^;]*;[^;]*;\([^;]*\)"_"\2-\1"_g
The desired output is:
Madonna-Falling Free
Madonna-I don't give a
Madonna-I'm a sinner
Madonna-Give Me All Your Luvin'
However, I am getting this:
Madonna-Falling Free;Madonna;Pop August 2013;MDNA;I don't give a;00:45:40;Madonna;Madonna;Pop August 2013;MDNA;I'm a sinner;01:00:29;Madonna;Madonna;Pop August 2013;MDNA;Give Me All Your Luvin';01:15:02;Madonna;Madonna;Pop
Why?
EDIT: I need to use sed.
When I run your sed script on your input, I get this output:
Madonna-Falling Free;Pop
Madonna-I don't give a;Pop
Madonna-I'm a sinner;Pop
Madonna-Give Me All Your Luvin';Pop
which is fine except for the extra ;Pop - you just need to add .*$ to the end of your regex so that the entire line is replaced.
Based on your reported output, I'm guessing your input file is using a different newline convention from what sed expects.
In any case, this is a pretty silly thing to use sed for. Much better with awk, for instance:
awk 'BEGIN {FS=";";OFS="-"} {print $5,$3}'
or, slightly more tersely,
awk -F\; -vOFS=- '{print $5,$3}'
If you want sed to see more than one line of input, you must quote the variable to echo:
echo "$LINES" | sed ...
Note that I'm not even going to try to evaluate the correctness of your sed script; using sed here is a travesty, given that awk is so much better suited to the task.
It looks like sed is viewing your entire sample text as a single line. So it is performing the operation requested and then leaving the rest unchanged.
I would look into the newline issue first. How are you populating $LINES?
You should also add to the pattern that seventh field in your input (genre), so that the expression actually does consume all of the text that you want it to. And perhaps anchor the end of the pattern on $ or \b (word boundary) or \s (a spacey character) or \n (newline).
If your format is absolutely permanent, just try below:
echo $line | sed 's#.*;.*;\(.*\);.*;.*;\(.*\);.*#\2-\1#'
For some reason I can't seem to find a straightforward answer to this and I'm on a bit of a time crunch at the moment. How would I go about inserting a choice line of text after the first line matching a specific string using the sed command. I have ...
CLIENTSCRIPT="foo"
CLIENTFILE="bar"
And I want insert a line after the CLIENTSCRIPT= line resulting in ...
CLIENTSCRIPT="foo"
CLIENTSCRIPT2="hello"
CLIENTFILE="bar"
Try doing this using GNU sed:
sed '/CLIENTSCRIPT="foo"/a CLIENTSCRIPT2="hello"' file
if you want to substitute in-place, use
sed -i '/CLIENTSCRIPT="foo"/a CLIENTSCRIPT2="hello"' file
Output
CLIENTSCRIPT="foo"
CLIENTSCRIPT2="hello"
CLIENTFILE="bar"
Doc
see sed doc and search \a (append)
Note the standard sed syntax (as in POSIX, so supported by all conforming sed implementations around (GNU, OS/X, BSD, Solaris...)):
sed '/CLIENTSCRIPT=/a\
CLIENTSCRIPT2="hello"' file
Or on one line:
sed -e '/CLIENTSCRIPT=/a\' -e 'CLIENTSCRIPT2="hello"' file
(-expressions (and the contents of -files) are joined with newlines to make up the sed script sed interprets).
The -i option for in-place editing is also a GNU extension, some other implementations (like FreeBSD's) support -i '' for that.
Alternatively, for portability, you can use perl instead:
perl -pi -e '$_ .= qq(CLIENTSCRIPT2="hello"\n) if /CLIENTSCRIPT=/' file
Or you could use ed or ex:
printf '%s\n' /CLIENTSCRIPT=/a 'CLIENTSCRIPT2="hello"' . w q | ex -s file
Sed command that works on MacOS (at least, OS 10) and Unix alike (ie. doesn't require gnu sed like Gilles' (currently accepted) one does):
sed -e '/CLIENTSCRIPT="foo"/a\'$'\n''CLIENTSCRIPT2="hello"' file
This works in bash and maybe other shells too that know the $'\n' evaluation quote style. Everything can be on one line and work in
older/POSIX sed commands. If there might be multiple lines matching the CLIENTSCRIPT="foo" (or your equivalent) and you wish to only add the extra line the first time, you can rework it as follows:
sed -e '/^ *CLIENTSCRIPT="foo"/b ins' -e b -e ':ins' -e 'a\'$'\n''CLIENTSCRIPT2="hello"' -e ': done' -e 'n;b done' file
(this creates a loop after the line insertion code that just cycles through the rest of the file, never getting back to the first sed command again).
You might notice I added a '^ *' to the matching pattern in case that line shows up in a comment, say, or is indented. Its not 100% perfect but covers some other situations likely to be common. Adjust as required...
These two solutions also get round the problem (for the generic solution to adding a line) that if your new inserted line contains unescaped backslashes or ampersands they will be interpreted by sed and likely not come out the same, just like the \n is - eg. \0 would be the first line matched. Especially handy if you're adding a line that comes from a variable where you'd otherwise have to escape everything first using ${var//} before, or another sed statement etc.
This solution is a little less messy in scripts (that quoting and \n is not easy to read though), when you don't want to put the replacement text for the a command at the start of a line if say, in a function with indented lines. I've taken advantage that $'\n' is evaluated to a newline by the shell, its not in regular '\n' single-quoted values.
Its getting long enough though that I think perl/even awk might win due to being more readable.
A POSIX compliant one using the s command:
sed '/CLIENTSCRIPT="foo"/s/.*/&\
CLIENTSCRIPT2="hello"/' file
Maybe a bit late to post an answer for this, but I found some of the above solutions a bit cumbersome.
I tried simple string replacement in sed and it worked:
sed 's/CLIENTSCRIPT="foo"/&\nCLIENTSCRIPT2="hello"/' file
& sign reflects the matched string, and then you add \n and the new line.
As mentioned, if you want to do it in-place:
sed -i 's/CLIENTSCRIPT="foo"/&\nCLIENTSCRIPT2="hello"/' file
Another thing. You can match using an expression:
sed -i 's/CLIENTSCRIPT=.*/&\nCLIENTSCRIPT2="hello"/' file
Hope this helps someone
The awk variant :
awk '1;/CLIENTSCRIPT=/{print "CLIENTSCRIPT2=\"hello\""}' file
I had a similar task, and was not able to get the above perl solution to work.
Here is my solution:
perl -i -pe "BEGIN{undef $/;} s/^\[mysqld\]$/[mysqld]\n\ncollation-server = utf8_unicode_ci\n/sgm" /etc/mysql/my.cnf
Explanation:
Uses a regular expression to search for a line in my /etc/mysql/my.cnf file that contained only [mysqld] and replaced it with
[mysqld]
collation-server = utf8_unicode_ci
effectively adding the collation-server = utf8_unicode_ci line after the line containing [mysqld].
I had to do this recently as well for both Mac and Linux OS's and after browsing through many posts and trying many things out, in my particular opinion I never got to where I wanted to which is: a simple enough to understand solution using well known and standard commands with simple patterns, one liner, portable, expandable to add in more constraints. Then I tried to looked at it with a different perspective, that's when I realized i could do without the "one liner" option if a "2-liner" met the rest of my criteria. At the end I came up with this solution I like that works in both Ubuntu and Mac which i wanted to share with everyone:
insertLine=$(( $(grep -n "foo" sample.txt | cut -f1 -d: | head -1) + 1 ))
sed -i -e "$insertLine"' i\'$'\n''bar'$'\n' sample.txt
In first command, grep looks for line numbers containing "foo", cut/head selects 1st occurrence, and the arithmetic op increments that first occurrence line number by 1 since I want to insert after the occurrence.
In second command, it's an in-place file edit, "i" for inserting: an ansi-c quoting new line, "bar", then another new line. The result is adding a new line containing "bar" after the "foo" line. Each of these 2 commands can be expanded to more complex operations and matching.