How would this be written to be on a single line?
in_file = open(from_file)
indata = in_file.read
File.read("/path/to/file")
It will read whole file content and return it as a result.
open("README.md").read
For very small file, this is acceptable.
Related
I have a file, that has variations of this line multiple times:
source = "git::https://github.com/ORGNAME/REPONAME.git?ref=develop"
I am passing through a tag name in a variable. I want to find every line that starts with source and update that line in the file to be
source = "git::https://github.com/ORGNAME/REPONAME.git?ref=$TAG"
This should be able to be done with awk and sed, but having some difficulty making it work. Any help would be much appreciated!
Best,
Keren
Edit: In this scenario, the it says "develop", but it could also be set to "feature/test1" or "0.0.1" as well.
Edit2: The line with "source" is also indented by three or four spaces.
This should do:
sed 's/^\([[:blank:]]*source.*[?]ref=\)[^"]*\("\)/\1'"$TAG"'\2/' file
with sed
$ sed '/^source/s/ref=develop"$/ref=$TAG"/' file
replace ref=develop" at the end of line with ref=$TAG" for lines starting with source.
Looking for help creating a script that will replace the last line of an XML file with a tag. I have a few hundred files so I'm looking for something that will process them in a loop. I've managed to rename the files sequentially like this:
posts1.xml
posts2.xml
posts3.xml
etc...
to make it easier to loop through. But I have no idea how to write a script to do this. I'm open to using either Linux or Windows (but i would guess that Linux is better for this kind of task).
So if you want to append a line to every file:
sed -i '$a<YOUR_SHINY_NEW_TAG>' *xml
To replace the last line:
sed -i '$s/.*/<YOUR_SHINY_NEW_TAG>/' *xml
But do note, sed is not the ideal tool to modify xml.
XMLStarlet is a command-line toolkit for performing XML parsing and manipulations. Note that as an XML-aware toolkit, it'll respect XML structure, character encoding and entity substitution.
Check out the ed command to see how to modify documents. You can wrap this in a standard bash loop.
e.g. in a doc consisting of a chain of <elem>s, you can add a following <added>5</added>:
mkdir new
for x in *.xml; do
xmlstarlet ed -a "//elem[count(//elem)]" -t elem -n added -v 5 $x > new/$x
done
Linux way using sed:
To edit the last line of the file in place, you can use sed:
sed -i '$s_pattern_replacement_' filename
To change the whole line to "replacement" use $s_.*_replacement_. Be sure to escape any _'s in replacement with a \.
To loop over files, just use for:
for f in /path/posts*.xml; do sed -i '$s_.*_replacement_' $f; done
This, however, is a dirty way as it's not aware of the XML structure, whereas the XML structure is not affected by newlines. You have to be sure the last line of the files contains exactly what you expect it to.
It makes little to no difference whether you're on Linux, Windows or MacOS
The question is what language do you want to use?
The following is an example in c# (not optimized, but read it as speudocode):
string rootDirectory = #"c:\myfiles";
var files = Directory.GetFiles(rootDirectory, "*.xml");
foreach (var file in files)
{
var lines = File.ReadAllLines(file);
lines[lines.Length - 1] = "whatever you want here";
File.WriteAllLines(file, lines);
}
You can compile this and run it on Windows, Linux, etc..
Or you could do the same in Python.
Of course this method does not actually parse the XML,
but you just wanted to replace the last line right?
I have a script that dumps data from a serial port to both a terminal and the harddrive. The output to the terminal looks fine, however the file write an ^M after each resulting in an extra newline for every other line.
The offending code:
# run and dump to file.
loop {
# output data to log file.
data = sp.read
data.delete!("\C-M") # Removes escape character.
if( data != "" )
puts data
File.open($log_file, 'a') { |f| f.write( data ) }
end
}
Example output:
On the terminal:
1
2
3
In the file
1
2
3
Edit: The solution is to run data.delete!("\C-M") after the read.
Try opening the data written to the file in ruby with read. I suspect the problem you have is with the carriage return characters that sometimes cause problems when transferring a file from windows to linux or when downloading files via some mail clients.
I don't know how your serial data looks like, but you can always do a chomp on data variable before writing. Try it and see how it goes.
Edit: If you want to remove the ^M, maybe you can try sp.read.tr("\r","")
I am trying to process a CSV file that can either be generated with CF or LF as an EOL marker. When I try to read the file with
infile = File.open('my.csv','r')
while line = infile.gets
...
The entire 20MB file is read in as one line.
How can I detect and handle properly?
TIA
I would slurp the file, normalize the input, and then feed it to CSV:
raw = File.open('my.csv','rb',&:read).gsub("\r\n","\n")
CSV.parse(raw) do |row|
# use row here...
end
The above uses File.open instead of IO.read due to slow file reads on Windows Ruby.
When in doubt, use a regex.
> "how\r\nnow\nbrown\r\ncow\n".split /[\r\n]+/
=> ["how", "now", "brown", "cow"]
So, something like
infile.read.split(/[\r\n]+/).each do |line|
. . .
end
Now, it turns out that the standard library CSV already understands mixed line endings, so you could just do:
CSV.parse(infile.read).each do |line|
. . .
How would you create a variable that could be read. It would read from a certain file if it exists, otherwise it would read from standard input. Something like:
input = File.open("file.txt") || in
This doesn't work, but I think this should be done pretty often, but I can't find a nice way to do it.
This this works for you?
input = File.exist?("file.txt") ? File.open("file.txt") : STDIN
See: ...run against stdin if no arg; otherwise input file =ARGV
I think ruby has the ability to treat arguments that aren't used before STDIN is first used as if it were filenames for files piped into standard input.