I have a large text file that I would like to divide into segments and use sed to delete certain patterns in place. I would like to do this in a single command line using a pipe. For example:
sed -n 1,10p <text file> | sed -i 's/<pattern to remove>//'
The code above attempts to take the first 10 lines of the text file and remove the patterns from the 10 lines in place. The resulting text file should have the first 10 lines modified. The code above doesn't work because the second command after the pipe requires a input file. Please help!
Something like
sed -i '1,10s/pattern//' foo.txt
though for in place editing of a file I prefer ed or perl instead of relying on a non standard sed extension like -i.
This seems to do what you're asking ....
sed -ni '1,10s/pattern//p' file
Related
I have 70+ strings I need to find and delete in a file. I need to remove the entire line in the file that the string appears in.
I know I can use sed -i '/string to remove/d' fileA.txt to remove them one at a time. However, considering I have 70+, it will take some time doing it this way.
Is there a way I can put these 70+ strings in a file and have sed go through them one by one? Or if I create a file containing the strings, is there a way to compare the two files so it removes any line from fileA that contains one of the strings?
You could use grep:
grep -vf file_with_words.txt file.txt
where file_with_words.txt would be the file containing the list of words, each word being on a different line and file.txt is the file that you want to remove the lines from.
If your list of words contains regex metacharacters, then tell grep to consider those as fixed strings (if that is what you want):
grep -F -vf file_with_words.txt file.txt
Using sed, you'd need to say:
sed '/word1\|word2\|word3/d' file.txt
or
sed -E '/word1|word2|word3/d' file.txt
You could use command substitution to construct the pattern too:
sed -E "/$(paste -sd'|' file_with_words.txt)/d" file.txt
but grep is clearly the tool to use in this case.
If you want to do the job in bash, here's how:
search=fileA.txt
queries=queries.txt
while read query
do
sed -i '' "/$query/d" $search
done < "$queries"
where queries.txt looks like
I
want
to
delete
these
lines
I'm trying to figure out how to efficiently copy-paste from X application to the terminal. Specifically I want to highlight a text section in my web browser, then paste this commented to a file after the shebang line.
the code I have so far is this:
xclip -o | sed 's/^/#/' | sed '2n' myscript.pl
the first command takes the text that I have highlighted in my browser
the second command comments the lines by adding #
the last bit does not work..
what I am trying to do here is append the text after line number 2 to my script. But obviously I am doing this wrong.. Does anyone have a helpful suggestion?
You can use sed read for safely handling all types of input, including input with special characters and multiple lines. This requires an intermediate file:
xclip -o | sed -e 's/^/#/g' -e '$s/$/\n/' > TMP && sed -i '1r TMP' den && rm TMP
sed only operates on one input stream (either a pipe or a file), if you are using the output of xclip as the data stream then you can't also tell sed to read from a file. Instead you could use command substitution to store the modified output, and use that in a separate command. How about:
sed "2i$(xclip -o | sed 's/^/#/')" myscript.pl
This will print the amended file to stdout, if you want to edit the file itself then use the -i flag.
I want to edit a file from the command line, because opening it in vim or other editors takes forever (a large file). I want to add a string ('chr') to the beginning of every line that is not commented out with a #. The command I am using is this:
cat '/home/me/37.vcf' | sed s/^/chr/>'sp.vcf'
But it adds a chr to the beginning of EVERY line and a > to the END of every line. I don't want either of those things to occur.
Can anyone offer any suggestions to improve my results?
To apply the substitution to only the lines that don't start with a #:
sed '/^[^#]/s/^/chr/' file > output
Note: the command cat is for concatenating files, it is useless here.
You can syntax error in your sed command. Use this syntactically correct sed command:
sed -E 's/^([^#]|$)/chr/' /home/me/37.vcf > sp.vcf
OR on Linux:
sed -r 's/^([^#]|$)/chr/' /home/me/37.vcf > sp.vcf
This might work for you (GNU sed):
sed '/^\s*#/!s/^/chr/' file > new_file
I need to edit a few text files (an output from sar) and convert them into CSV files.
I need to change every whitespace (maybe it's a tab between the numbers in the output) using sed or awk functions (an easy shell script in Linux).
Can anyone help me? Every command I used didn't change the file at all; I tried gsub.
tr ' ' ',' <input >output
Substitutes each space with a comma, if you need you can make a pass with the -s flag (squeeze repeats), that replaces each input sequence of a repeated character that is listed in SET1 (the blank space) with a single occurrence of that character.
Use of squeeze repeats used to after substitute tabs:
tr -s '\t' <input | tr '\t' ',' >output
Try something like:
sed 's/[:space:]+/,/g' orig.txt > modified.txt
The character class [:space:] will match all whitespace (spaces, tabs, etc.). If you just want to replace a single character, eg. just space, use that only.
EDIT: Actually [:space:] includes carriage return, so this may not do what you want. The following will replace tabs and spaces.
sed 's/[:blank:]+/,/g' orig.txt > modified.txt
as will
sed 's/[\t ]+/,/g' orig.txt > modified.txt
In all of this, you need to be careful that the items in your file that are separated by whitespace don't contain their own whitespace that you want to keep, eg. two words.
without looking at your input file, only a guess
awk '{$1=$1}1' OFS=","
redirect to another file and rename as needed
What about something like this :
cat texte.txt | sed -e 's/\s/,/g' > texte-new.txt
(Yes, with some useless catting and piping ; could also use < to read from the file directly, I suppose -- used cat first to output the content of the file, and only after, I added sed to my command-line)
EDIT : as #ghostdog74 pointed out in a comment, there's definitly no need for thet cat/pipe ; you can give the name of the file to sed :
sed -e 's/\s/,/g' texte.txt > texte-new.txt
If "texte.txt" is this way :
$ cat texte.txt
this is a text
in which I want to replace
spaces by commas
You'll get a "texte-new.txt" that'll look like this :
$ cat texte-new.txt
this,is,a,text
in,which,I,want,to,replace
spaces,by,commas
I wouldn't go just replacing the old file by the new one (could be done with sed -i, if I remember correctly ; and as #ghostdog74 said, this one would accept creating the backup on the fly) : keeping might be wise, as a security measure (even if it means having to rename it to something like "texte-backup.txt")
This command should work:
sed "s/\s/,/g" < infile.txt > outfile.txt
Note that you have to redirect the output to a new file. The input file is not changed in place.
sed can do this:
sed 's/[\t ]/,/g' input.file
That will send to the console,
sed -i 's/[\t ]/,/g' input.file
will edit the file in-place
Here's a Perl script which will edit the files in-place:
perl -i.bak -lpe 's/\s+/,/g' files*
Consecutive whitespace is converted to a single comma.
Each input file is moved to .bak
These command-line options are used:
-i.bak edit in-place and make .bak copies
-p loop around every line of the input file, automatically print the line
-l removes newlines before processing, and adds them back in afterwards
-e execute the perl code
If you want to replace an arbitrary sequence of blank characters (tab, space) with one comma, use the following:
sed 's/[\t ]+/,/g' input_file > output_file
or
sed -r 's/[[:blank:]]+/,/g' input_file > output_file
If some of your input lines include leading space characters which are redundant and don't need to be converted to commas, then first you need to get rid of them, and then convert the remaining blank characters to commas. For such case, use the following:
sed 's/ +//' input_file | sed 's/[\t ]+/,/g' > output_file
This worked for me.
sed -e 's/\s\+/,/g' input.txt >> output.csv
I have a set of 10 CSV files, which normally have a an entry of this kind
a,b,c,d
d,e,f,g
Now due to some error entries in this file have become of this kind
a,b,c,d
d,e,f,g
,,,
h,i,j,k
Now I want to remove the line with only commas in all the files. These files are on a Linux filesystem.
Any command that you recommend that can replaces the erroneous lines in all the files.
It depends on what you mean by replace. If you mean 'remove', then a trivial variant on #wnoise's solution is:
grep -v '^,,,$' old-file.csv > new-file.csv
Note that this deletes just those lines with exactly three commas. If you want to delete mal-formed lines with any number of commas (including zero) - and no other characters on the line, then:
grep -v '^,*$' ...
There are endless other variations on the regex that would deal with other scenarios. Dealing with full CSV data with commas inside quotes starts to need something other than a regex machine. It can be done, within broad limits, especially in more complex regex systems such as PCRE or Perl. But it requires more work.
Check out Mastering Regular Expressions.
sed 's/,,,/replacement/' < old-file.csv > new-file.csv
optionally followed by
mv new-file.csv old-file.csv
Replace or remove, your post is not clear... For replacement see wnoise's answer. For removing, you could use
awk '$0 !~ /,,,/ {print}' <old-file.csv > new-file.csv
What about trying to keep only lines which are matching the desired format instead of handling one exception ?
If the provided input is what you really want to match:
grep -E '[a-z],[a-z],[a-z],[a-z]' < oldfile.csv > newfile.csv
If the input is different, provide it, the regular expression should not be too hard to write.
Do you want to replace them with something, or delete them entirely? Either way, it can be done with sed. To delete:
sed -i -e '/^,\+$/ D' yourfile1.csv yourfile2.csv ...
To replace: well, see wnoise's answer, or if you don't want to create new files with the output,
sed -i -e '/^,\+$/ s//replacement/' yourfile1.csv yourfile2.csv ...
or
sed -i -e '/^,\+$/ c\
replacement' yourfile1.csv yourfile2.csv ...
(that should be entered exactly as is, including the line break). Of course, you can also do this with awk or perl or, if you're only deleting lines, even grep:
egrep -v '^,+$' < oldfile.csv > newfile.csv
I tested these to make sure they work, but I'd advise you to do the same before using them (just in case). You can omit the -i option from sed, in which case it'll print out the results (rather than writing them back to the file), or omit the output redirection >newfile.csv from grep.
EDIT: It was pointed out in a comment that some features of these sed commands only work on GNU sed. As far as I can tell, these are the -i option (which can be replaced with shell redirection, sed ... <infile >outfile ) and the \+ modifier (which can be replaced with \{1,\} ).
Most simply:
$ grep -v ,,,, oldfile > newfile
$ mv newfile oldfile
yes, awk or grep are very good option if you are working in linux platform. However you can use perl regex for other platform. using join & split options.