Linux copy two files to one

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 can I copy several binary files into one file on a Linux system?

I need to copy the content of a folder which contains binary files to one binary file in another directory. In Windows I can just use:

copy file1 + file2 targetfile /B 

I couldn’t find something similar for Linux (I saw an approach with cat , but I’m unsure if this really works for binary files).

2 Answers 2

Unix has no distinction between text and binary files, which is why you can just cat them together:

cat file1 file2 > target_file 

If target_file already exists and you want to append content to it, instead of overwriting, use instead:

cat file1 file2 >> target_file 

Unfortunately this messes up the binary data. I guess it is caused by some encoding issue? ASCII strings inside the binary data are ok in the resulting file but bytes outside the ASCII range are messed up (I guess they are replaced by UTF-8 replacements?). How can I tell cat to ignore encodings and just concat the files byte per byte?

From what I read everywhere cat should not care about encodings and just work with binary files. But it doesn’t in my case. I use /bin/cat inside an appveyor Ubuntu environment. Maybe they use another cat?

Side note: if target_file exists in advance and you want to append content to it, rather than overwriting it, use the >> operator instead of >.

@ferdymercury Please do consider editing the answer to include the >> part; it saved me today. Typically comments aren’t read & thus would help someone as well 🙂

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How to Append Contents of Multiple Files Into One File on Linux?

There are many situations where you may need to combine the contents of multiple files into one file. For example, you may have a number of log files that need to be analyzed or you may want to merge multiple text documents into one document for easy editing. On Linux, there are several ways to aggregate the contents of multiple files into a single file, and in this article, we’ll explore some of the most popular and effective methods.

Method 1: Use the cat command

The «cat» command is a powerful tool on Linux that allows you to view and concatenate the contents of multiple files. To add the contents of multiple files into a single file using the «cat» command, follow these steps −

• Open a terminal window and navigate to the directory where the files you want to add are located.
• Use the «ls» command to list the files in the directory.
• Type the following command, replacing «file1» and «file2» with the names of the files you want to add −

$ cat file1 file2 >> combined_file

The «>>» operator adds the contents of «file1» and «file2» to the end of the «combined_file», creating it if it doesn’t already exist. If you want to add the contents of more than two files, simply add the names of the additional files to the command.

For example, to add the contents of three files named «file1», «file2», and «file3», use the following command −

$ cat file1 file2 file3 >> combined_file

You can also use wildcards to add the contents of multiple files at once. For example, to add all text files in the current directory, you can use the following command −

Method 2: Using the echo command

The «echo» command is another simple and effective way to add the contents of multiple files to a single file in Linux. To use the echo command to add the contents of multiple files, follow these steps −

• Open a terminal window and navigate to the directory where the files you want to add are located.
• Type the following command, replacing «file1» and «file2» with the names of the files you want to add −

$ echo " " >> combined_file $ echo "Contents of file1:" >> combined_file $ cat file1 >> combined_file $ echo " " >> combined_file $ echo "Contents of file2:" >> combined_file $ cat file2 >> combined_file

This command uses the «echo» command to add a blank line and header to the file «combined_file», followed by the contents of «file1» and «file2». If you want to add the contents of more than two files, simply add additional «echo» and «cat» commands for each file.

Method 3: Use the sed command

The «sed» command is a powerful tool in Linux that allows you to find and replace text in a file. You can also use the «sed» command to add the contents of multiple files into a single file. To use the «sed» command to add the contents of multiple files, follow these steps:

• Open a terminal window and navigate to the directory where the files you want to add are located.
• Type the following command, replacing «file1» and «file2» with the names of the files you want to add −

$ sed '$ a ' file1 file2 >> combined_file

The «$» operator in the «sed» command specifies the end of the file, and the «a» command means «add». The text following the «a» command is appended to the end of the file. In this case, we’re using the «» character to escape the newline character, which allows us to add the contents of «file1» and «file2» to the end of the «merged_file» file on separate lines.

If you want to add the contents of more than two files, simply add the names of the additional files to the command. For example, to add the contents of three files named «file1», «file2», and «file3», use the following command −

$ sed '$ a ' file1 file2 file3 >> combined_file

Method 4: Using the paste command

The «paste» command is another useful tool in Linux that allows you to merge the contents of multiple files into one file. To use the paste command to add the contents of multiple files, do the following −

• Open a terminal window and navigate to the directory where the files you want to add are located.
• Type the following command, replacing «file1» and «file2» with the names of the files you want to add −

$ paste file1 file2 >> combined_file

Press Enter to run the command. The «paste» command combines the contents of «file1» and «file2» into a single file, with each line of each file separated by a tab character. If you want to add the contents of more than two files, simply add the names of the additional files to the command.

Conclusion

In this article, we have explored four different methods to aggregate the contents of multiple files into a single file on Linux. Each method has its advantages and limitations, and the best method for your specific needs will depend on your specific project requirements. Regardless of which method you choose, the ability to merge multiple files into a single file is a powerful tool in Linux that can save you time and effort when working with large volumes of data.

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