Add a comment. Active Oldest Votes. Only the file part of the remote file is used, the path is cut off. Instead, you should use either: curl -o Chicago. Tippa Raj Tippa Raj 4 4 silver badges 8 8 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. It is to be noted that the command given above is for only Debian based Linux systems such as Ubuntu.
If a user has a Red Hat Linux system such as Fedora, then the user needs to enter the following command into the command line:. As mentioned before, Wget has multiple features incorporated inside of it. The most basic operation that Wget offers to users is downloading files by simply using its URL.
This can be done by inputting the following command into the terminal:. Let us show an example to further clarify this. We will be downloading a simple image in the png format from the internet.
See the image below for better understanding:. Wget also allows users to download multiple files from different URLs. This can easily be done by the following command:.
Once again, we can show this using an example. We will be downloading two HTML files from two different websites. For better understanding, please look at the image below:. Finally, the results of this string of operations are placed in a new file named onlydata. You can easily change the delimiter of a file using the tr command. To convert a tab-separated values file named input. This section provides a few ways of doing this.
In the previous recipe, we removed comments and the header from a CSV file. We did so, because we knew beforehand that they existed in the data set. Instead of opening the file, which could be quite large, with a text editor, we can quickly use the head command:. This command will display the first 10 lines of input. To see more or fewer lines, we can specify the number using the -n argument:. If we want to search the whole file for comments, we can use grep:.
Which prints each line in input. If we instead want to know the number of comments that occur in the file, we can send the output to the wc command, which can count the number of lines in the output of grep when used with the -l argument:.
If the output from this command is 0, then we know that input. The wc command lists the number of lines in a file when the -l argument is given. It does so indiscriminately, so its count will include headers and comments. Using previous recipes, though, we can strip these things from the file before counting the number of lines.
This command will print out the input. The output of this is sent to sed , which strips out the header on the first line assuming we have one—see previous recipe. The result of all this is then sent to wc , which counts and prints the number of lines, each of which is presumably a data record. Similarly, we can determine the number of columns in the data set by looking at the non-comment lines:. This command uses grep to strip out commented rows, and sends the remaining rows to awk , which reports the number of comma-separated fields the FS argument in each line.
We can send these results to the uniq command to only output the unique numbers of columns present in the file:. Typically, all rows in a CSV file contain the same number of records. In that case, the command will return one number. If more than one number is returned, there is some variation in the number of records per line in the file, which could cause other problems. If some of our records are stored in one file, say input1. It is important to note that each of the files should contain the same number of columns and have those columns occurring in the same order.
Recipes for extracting specific columns in order to rearrange them are included later. If each of the input files has a header, each of those header lines will be copied into combined. The easiest way to deal with this is to strip the header line from each file as we combine them:. Sign up using Email and Password.
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