Files in one file command linux

How to append contents of multiple files into one file

and it did not work. I want my script to add the newline at the end of each text file. eg. Files 1.txt, 2.txt, 3.txt. Put contents of 1,2,3 in 0.txt How do I do it ?

12 Answers 12

You need the cat (short for concatenate) command, with shell redirection ( > ) into your output file

@blasto it depends. You would use >> to append one file onto another, where > overwrites the output file with whatever’s directed into it. As for the newline, is there a newline as the first character in file 1.txt ? You can find out by using od -c , and seeing if the first character is a \n .

@blasto You’re definitely heading in the right direction. Bash certainly accepts the form <. >for filename matching, so perhaps the quotes messed things up a bit in your script? I always try working with things like this using ls in a shell. When I get the command right, I just cut-n-paste it into a script as is. You might also find the -x option useful in your scripts — it will echo the expanded commands in the script before execution.

To maybe stop somebody from making the same mistake: cat 1.txt 2.txt > 1.txt will just override 1.txt with the content of 2.txt . It does not merge the two files into the first one.

Another option, for those of you who still stumble upon this post like I did, is to use find -exec :

find . -type f -name '*.txt' -exec cat <> + >> output.file 

In my case, I needed a more robust option that would look through multiple subdirectories so I chose to use find . Breaking it down:

Look within the current working directory.

Only interested in files, not directories, etc.

Whittle down the result set by name

Execute the cat command for each result. «+» means only 1 instance of cat is spawned (thx @gniourf_gniourf)

As explained in other answers, append the cat-ed contents to the end of an output file.

There are lots of flaws in this answer. First, the wildcard *.txt must be quoted (otherwise, the whole find command, as written, is useless). Another flaw comes from a gross misconception: the command that is executed is not cat >> 0.txt <> , but cat <> . Your command is in fact equivalent to < find . -type f -name *.txt -exec cat '<>‘ \; ; > >> 0.txt (I added grouping so that you realize what’s really happening). Another flaw is that find is going to find the file 0.txt , and cat will complain by saying that input file is output file.

Thanks for the corrections. My case was a little bit different and I hadn’t thought of some of those gotchas as applied to this case.

You should put >> output.file at the end of your command, so that you don’t induce anybody (including yourself) into thinking that find will execute cat <> >> output.file for every found file.

Starting to look really good! One final suggestion: use -exec cat <> + instead of -exec cat <> \; , so that only one instance of cat is spawned with several arguments ( + is specified by POSIX).

Good answer and word of warning — I modified mine to: find . -type f -exec cat <> + >> outputfile.txt and couldn’t figure out why my output file wouldn’t stop growing into the gigs even though the directory was only 50 megs. It was because I kept appending outputfile.txt to itself! So just make sure to name that file correctly or place it in another directory entirely to avoid this.

if you have a certain output type then do something like this

cat /path/to/files/*.txt >> finalout.txt 

Keep in mind that you are losing the possibility to maintain merge order though. This may affect you if you have your files named, eg. file_1 , file_2 , … file_11 , because of the natural order how files are sorted.

If all your files are named similarly you could simply do:

If all your files are in single directory you can simply do

Files 1.txt,2.txt, .. will go into 0.txt

Already answered by Eswar. Keep in mind that you are losing the possibility to maintain merge order though. This may affect you if you have your files named, eg. file_1 , file_2 , … file_11 , because of the natural order how files are sorted.

for i in ; do cat "$i.txt" >> 0.txt; done 

I found this page because I needed to join 952 files together into one. I found this to work much better if you have many files. This will do a loop for however many numbers you need and cat each one using >> to append onto the end of 0.txt.

as brought up in the comments:

sed r 1.txt 2.txt 3.txt > merge.txt 

sed h 1.txt 2.txt 3.txt > merge.txt 

sed -n p 1.txt 2.txt 3.txt > merge.txt # -n is mandatory here 

sed wmerge.txt 1.txt 2.txt 3.txt 

Note that last line write also merge.txt (not wmerge.txt !). You can use w»merge.txt» to avoid confusion with the file name, and -n for silent output.

Of course, you can also shorten the file list with wildcards. For instance, in case of numbered files as in the above examples, you can specify the range with braces in this way:

if your files contain headers and you want remove them in the output file, you can use:

for f in `ls *.txt`; do sed '2,$!d' $f >> 0.out; done 

All of the (text-) files into one

find . | xargs cat > outfile 

xargs makes the output-lines of find . the arguments of cat.

find has many options, like -name ‘*.txt’ or -type.

you should check them out if you want to use it in your pipeline

You should explain what your command does. Btw, you should use find with —print0 and xargs with -0 in order to avoid some caveats with special filenames.

If the original file contains non-printable characters, they will be lost when using the cat command. Using ‘cat -v’, the non-printables will be converted to visible character strings, but the output file would still not contain the actual non-printables characters in the original file. With a small number of files, an alternative might be to open the first file in an editor (e.g. vim) that handles non-printing characters. Then maneuver to the bottom of the file and enter «:r second_file_name». That will pull in the second file, including non-printing characters. The same could be done for additional files. When all files have been read in, enter «:w». The end result is that the first file will now contain what it did originally, plus the content of the files that were read in.

Send multi file to a file(textall.txt):

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How To Combine Text Files in Linux

A file is a collection of data stored in a computer system mainly identified by its filename. We need to combine multiple files in an organized manner and keep them in one place. The cat command helps Linux users to combine text files.

You can also use cat commands for multiple operations, such as creating single or multiple files, viewing their contents, merging files, and displaying the output to a screen. It can even redirect these contents to files. If you also want to know the approach to combining text files, then don’t worry. In this guide, you will get to know about the ways to combine text files in Linux.

How To Combine Text Files in Linux

First, let’s find all the available options in the cat command. Then execute the following command:

Let’s begin with an example where you want to combine f1.txt, f2.txt, and f3.txt files into f4.txt. Using the following command, you can accomplish the task:

In case you don’t want to overwrite the f4.txt file, use the following command:

As you can see in the previous images, there is a massive difference in the result of both commands.

You can use the following cat command to view the file’s contents without opening it:

You can use the cat command, followed by the pipe command (|) and the sort command to sort the combined text files in an ordered list pattern.

After that, use the output redirection symbol (>) with the file’s name into which the combined text is to be copied. After that, all the lines of text in the result file will get sorted in alphabetical order. The command should be:

You can view the contents of a file with line numbers. Use -n followed by the name of the file as:

If you want to combine multiple large files, then instead of specifying each file’s name to be concatenated, use the wildcards to identify these files, followed by an output redirection symbol.

Hence, it is possible to concatenate all the files in the current directory using an asterisk (*) symbol wildcard as:

We can use the pipe symbol and the echo command that will feed all the files in the current directory to the cat command as:

Conclusion

The Linux operating system provides a variety of commands to combine text files into one file in an organized way. In this detailed guide, we have used different techniques to combine two text files into one file alphabetically or numerically utilizing the cat command. The cat command can be handy when combined with another command in different situations. We hope this guide helped you understand the straightforward approach to combining text files in Linux.

About the author

Prateek Jangid

A passionate Linux user for personal and professional reasons, always exploring what is new in the world of Linux and sharing with my readers.

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Merge Files in the Linux Command Line

Learn various ways of merging multiple files into another file in the Linux command line.

Got two or more files and need to merge them in a single file? The simplest way would be to use the cat command. After all, the cat command’s original purpose is to concatenate files.

Use the cat command to merge files in Linux

Merging two files is simple. You just have to append the filename to the cat command and that’s it:

As you can see, I used the cat command to show the contents of a file and then merged them.

But it won’t save any changes. To save those changes, you have to redirect the file contents to another file.

Remember, the > will override the contents of the file so I would recommend using a new file as the cat will create the file if it doesn’t exist.

So how can you modify the editing file while keeping the previous content intact?

Append changes to the existing file

To modify the existing file, you just have to use >> instead of single > and you’d be good to go.

For example, I will make edit the existing file File_3.txt by appending Hello.txt and Sagar.txt :

As you can see, it added new text in the end line while keeping the old content intact.

Automate the merging files using the loop in Linux

Here, I will be using for loop (till three iterations as I want to merge three files) also you can use > or >> as per your needs.

for i in ; do cat "File_$i.txt" >> NewFile.txt; done

Use the sed command to merge files in Linux (temporary)

There are many times when you want to apply changes only for a specific time and in those cases, you can use sed.

Being a non-interactive way of editing files, the sed utility can be tremendously useful when used in the right way.

And when used with the h flag, it will hold the buffer temporarily:

Wrapping Up

This was my take on how you can merge files using the sed and cat command. And if you have any queries, leave us a comment.

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