Programming :: Insert Line Of Text Prior To Pattern Only Once?
Jun 29, 2010
I have a file like so:
Code:
one
two
three
four
I would like to insert prior to the word "three" all items from this second file with the following contents:
Code:
four
three
two
one
Now my issue is, and I have been using both sed and awk currently, that after the second line of the new file is read there will of course now be 2 copies of the word "three" but I would like to only insert the final 2 words, ie "two" and "one" prior to only the first occurrence of the word "three" so final file will look like:
Code:
one
two
four
[code]....
So here there is now only one of each word from the second file joined to make the new file. For simple code I have tried something like the following:
Code:
while read line
do
awk -v n=$line '!f && /three/{print n;f++}1' file1 > tmp_file
mv tmp_file file1
done < file2
Now this works but seems very clumsy to me. There is obviously a better sed and / or awk out there.
I want to search a file for a particular pattern and if pattern found replace the line with new text. i am using awk 'match($0,"pattern") != 0 {print $0} ' filename to check if the pattern exists.how do i get the line number of the pattern and delete that line and replace the line with my new text?
I am trying to create a shell script, on taking a input file as parameter, which need to do 3 things
1) create a copy of existing file.
2) add a new line to the copied file.
3) strip off all the absolute paths inside the copied file
The first 2 points are straight forward. but i am finding it difficult to acheive the 3rd point. myself not very good with awk and sed. but gave it a shot in vain. For example, the input script consists of below,
I want to read from the file and check for the pattern, if the line has some word like <string>: then string should be copied into buffer. Afterwards, I want to insert the same <string> with some word in the next line of the file. use sed command to perform the above mentioned operations?
I need to run a command in a shell script to insert a line in a file, after it finds certain line. To add the line 'user = mysql' after the line [mysqld] in file /etc/my.cnf
if the given pattern exists in the file with the very next line starting and endingwith the same pattern , delete the line that starts and ends with the given pattern.So upon running on this file
hai people<PATTERN> we had <PATTERN>a lot of fun<PATTERN> writing scripts
I have a question about sed programming, actually a one-liner for which I cannot find a solution, right now. I need to delete a line matching a specific pattern only if it is the last line. In practice, I would put together the following:
Here's the actual line of code, which exists in a bash script:
Code:
I want to replace instances like this:
Code:
with this:
Code:
Using this:
Code:
Which works great when there's only ONE of the pattern on the line. But in a case like the "actual line" I posted first, where there are two patterns, separated by a slash, only ONE gets replaced
Watch:
Code:
Why? There must be (among many other things) something I'm not knowing about sed, that's causing this.
-- I'm currently using the ~ (tilde) as the separator in the sed command. It doesn't matter, I've used / ~ and % with no difference.
-- As a test, I tried putting a different character(s) in the middle of the original pattern instead of the / but that made no difference.
-- I've come up with various similar but slightly different regexs that will do this replacement, but they all have had this same result.
-- I tried the sed single-quoted, double-quoted, and unquoted; the latter fails to execute, and the formers both work as described here: wrong.
i trying to add text messge in textarea and i got error in connection and i don't know if it correct syntax. and i wonder when i was install xamp server it no password required. but i dont know what password that i input in my php connection.?
I'm trying to insert a line using sed that has leading spaces before the text. Sed seems to be just dropping the spaces and only inserting the text. Any ideas what I'm missing?
Code:
NAM=rb134 sed -i.bak -e "$i host ${NAM} {" /etc/crap
Instead of inserting a line with 8 leading spaces inserts it with "host" at the beginning of the line. I tried
Code:
NAM=rb134 sed -i.bak -e "$i ^ host ${NAM} {" /etc/crap
As indicated in the subject, I want to search a text. If the text is present I want to replace it. But if the text is not present, I want to insert it after first line and before last line.
I've been reading tutorials of Linux sed command, but haven't got anything yet. the problem is : I want to insert a line into my DNS database file which has a pattern like below:
<Domain name> 3tabs here <IN> <A> <ip address>
the question is : how to add a line into a file like this using linux sed command? I have problem inserting tabs and the spaces!
I have to delete a certain line of text from the a textfile via ubuntu's shell scripting.I have done research, and it seems that most people advocate the usage of sed /d option. sed makes does not edit the text file. Hence, most options I discovered involved the use of a temporary variable/textfile and then overwriting the old file with the temporary new file. Is there anyway whereby I can bypass the use of temporary storage containers? I hope there is any magical combination of commands to edit the file directly.
I have two txt files containing x and y coordinates: xcoord.txt & ycoord.txt. I need to open them; read them line by line to get each coordinate; then each time I need to update Xs and Ys parameters inside another file called "dc.in" with the grabbed values.
Finally each time I need to run two exe files ( dc_2002 and st_vac) and produce corresponding output for each Xs and Ys ( dc.in is an input file for this exe files)
I have written the following code but it does not work:
Was wondering if any perl guru's could help me with a quick log file adjustment. I have a text file that looks like so (tabs and newlines are revealed so you can see what separates the data):
There are maybe 100 lines of text in this file at any given time. I need to delete all duplicate lines only looking at the first bit of text prior to the first tab. It doesn't matter which one gets deleted as long as there are no two lines that begin with that same text at the beginning before the first tab. So in this example, either the fist line "1234" or the last line "1234" would need to be deleted. I already have code in my script that opens the files - I just need the code to read the text into an array and the part that would find matches based on the above criteria, and make the deletions.
If it would be easier, I can even do a system call and use SED (v4.1.5) and/or AWK (3.1.5) instead.
a sed command to add a text before line number in text file? I have text file with 500 lines, and i want to add 3 more lines with text after line 300, OR before line 302, isn't no problem.
bash 3.1.17(2) I'm trying do write a shell script which must operate on each line of an ASCII text file. So, all the code must be inside a loop, and inside the loop, the first thing should be to read the next line from the file. I have the bash read command. But it reads from stdin. Any way to make read from a file?
I'm a bit new to Python programming and hoped that someone might be able to help with a problem I'm having. What I essentially want to do is to combine two text files line for line. I know how to do this in a bash script so to give you a better idea here's the code for that:
Code:
This is basically for adding on values to the end of a CSV file that uses ';' as the delimiter. So say file1 said:
And file2 said:
Then running this command would create merged_file1_and_file2 which would be:
The code I'm using at the moment is:
Code:
As I'm sure any experienced python programmer will see, this prints out the first line of the file "csvraw" and then all of the lines of "stamps" and then the remainder of "csvraw".
What I'd like to do is something like: (pseudo code, I know it's not python ;-))
Code:
Is this possible? I've tried googling and my Python Pocket Reference hasn't been much help. I've looked at pickling but that doesn't seem appropriate.
I have to enhance the behaviour of a backup script written in perl. I don't need to change it, what I need to do is to create a bash script that does some checks like file name and file size, execute the backup script then check if the backup files match the original files.Here's how I try to do it:
- read the files from the original files folder - store them in an array - search in the array the files that have a specific file extension - store the file names that match the search pattern (I know the backup script skips some files so I can hardcode the search pattern) - run the backup script - read the files from the backup folder - store them in an array - compare the original files name and size stored in an array with those from the backup folder - send a report email
I'm trying to add text to a file for a specific group of users, I'll need to do examples as I can't think of an easy way of explaining, my file is like this:
Code:
users{ user1 user2
[code]....
At the present my code lists all the available groups, how would I add a user to a specified group? (e.g add "members user3") to the end of group 1 for example. So the code ends up like this