We come across files and folders name very regularly. In most of the cases file/folder name are related to the content of the file/folder and starts with number and characters. Alpha-Numeric file name are pretty common and very widely used, but this is not the case when we have to deal with file/folder name that has special characters in them.
Note: We can have files of any type but for simplicity and easy implementation we will be dealing with Text file (.txt), throughout the article.
Example of most common file names are:
abc.txt avi.txt debian.txt ...
Example of numeric file names are:
121.txt 3221.txt 674659.txt ...
Example of Alpha-Numeric file names are:
eg84235.txt 3kf43nl2.txt 2323ddw.txt ...
Examples of file names that has special character and is not very common:
#232.txt #bkf.txt #bjsd3469.txt #121nkfd.txt -2232.txt -fbjdew.txt -gi32kj.txt --321.txt --bk34.txt ...
One of the most obvious question here is – who on earth create/deal with files/folders name having a Hash (#), a semi-colon (;), a dash (-) or any other special character.
I Agree to you, that such file names are not common still your shell should not break/give up when you have to deal with any such file names. Also speaking technically every thing be it folder, driver or anything else is treated as file in Linux.
Dealing with file that has dash (-) in it’s name
Create a file that starts with a dash (-), say -abx.txt.
$ touch -abc.txt
Sample Output
touch: invalid option -- 'b' Try 'touch --help' for more information.
The reason for above error, that shell interprets anything after a dash (-), as option, and obviously there is no such option, hence is the error.
To resolve such error, we have to tell the Bash shell (yup this and most of the other examples in the article is for BASH) not to interpret anything after special character (here dash), as option.
There are two ways to resolve this error as:
$ touch -- -abc.txt [Option #1] $ touch ./-abc.txt [Option #2]
You may verify the file thus created by both the above ways by running commands ls or ls -l for long listing.
$ ls -l total 0 -rw-r--r-- 1 avi avi 0 Jun 8 11:05 -abc.txt
To edit the above file you may do:
$ nano -- -abc.txt or $ nano ./-abc.txt
Note: You may replace nano with any other editor of your choice say vim as:
$ vim -- -abc.txt or $ vim ./-abc.txt
Similarly to move such file you have to do:
$ mv -- -abc.txt -a.txt or $ mv -- -a.txt -abc.txt
and to Delete this file, you have to do:
$ rm -- -abc.txt or $ rm ./-abc.txt
If you have lots of files in a folder the name of which contains dash, and you want to delete all of them at once, do as:
$ rm ./-*
Important to Note:
1. The same rule as discussed above follows for any number of hypen in the name of the file and their occurrence. Viz., -a-b-c.txt, ab-c.txt, abc-.txt, etc.
2. The same rule as discussed above follows for the name of the folder having any number of hypen and their occurrence, except the fact that for deleting the folder you have to use ‘rm -rf‘ as:
$ rm -rf -- -abc or $ rm -rf ./-abc
Dealing with files having HASH (#) in the name
The symbol # has a very different meaning in BASH. Anything after a # is interpreted as comment and hence neglected by BASH.
Understand it using examples:
create a file #abc.txt.
$ touch #abc.txt
Sample Output
touch: missing file operand Try 'touch --help' for more information.
The reason for above error, that Bash is interpreting #abc.txt a comment and hence ignoring. So the command touch has been passed without any file Operand, and hence is the error.
To resolve such error, you may ask BASH not to interpret # as comment.
$ touch ./#abc.txt or $ touch '#abc.txt'
and verify the file just created as:
$ ls -l total 0 -rw-r--r-- 1 avi avi 0 Jun 8 12:14 #abc.txt
Now create a file the name of which contains # anywhere except at the begging.
$ touch ./a#bc.txt $ touch ./abc#.txt or $ touch 'a#bc.txt' $ touch 'abc#.txt'
Run ‘ls -l‘ to verify it:
$ ls -l total 0 -rw-r--r-- 1 avi avi 0 Jun 8 12:16 a#bc.txt -rw-r--r-- 1 avi avi 0 Jun 8 12:16 abc#.txt
What happens when you create two files (say a and #bc) at once:
$ touch a.txt #bc.txt
Verify the file just created:
$ ls -l total 0 -rw-r--r-- 1 avi avi 0 Jun 8 12:18 a.txt
Obvious from the above example it only created file ‘a‘ and file ‘#bc‘ has been ignored. To execute the above situation successfully we can do,
$ touch a.txt ./#bc.txt or $ touch a.txt '#bc.txt'
and verify it as:
$ ls -l total 0 -rw-r--r-- 1 avi avi 0 Jun 8 12:20 a.txt -rw-r--r-- 1 avi avi 0 Jun 8 12:20 #bc.txt
You can move the file as:
$ mv ./#bc.txt ./#cd.txt or $ mv '#bc.txt' '#cd.txt'
Copy it as:
$ cp ./#cd.txt ./#de.txt or $ cp '#cd.txt' '#de.txt'
You may edit it as using your choice of editor as:
$ vi ./#cd.txt or $ vi '#cd.txt'
$ nano ./#cd.txt or $ nano '#cd.txt'
And Delete it as:
$ rm ./#bc.txt or $ rm '#bc.txt'
To delete all the files that has hash (#) in the file name, you may use:
# rm ./#*
Dealing with files having semicolon (;) in its name
In case you are not aware, semicolon acts as a command separator in BASH and perhaps other shell as well. Semicolon lets you execute several command in one go and acts as separator. Have you ever deal with any file name having semicolon in it? If not here you will.
Create a file having semi-colon in it.
$ touch ;abc.txt
Sample Output
touch: missing file operand Try 'touch --help' for more information. bash: abc.txt: command not found
The reason for above error, that when you run the above command BASH interpret touch as a command but could not find any file operand before semicolon and hence it reports error. It also reports another error that ‘abc.txt‘ command not found, only because after semicolon BASH was expecting another command and ‘abc.txt‘, is not a command.
To resolve such error, tell BASH not to interpret semicolon as command separator, as:
$ touch ./';abc.txt' or $ touch ';abc.txt'
Note: We have enclosed the file name with single quote ''. It tells BASH that ; is a part of file name and not command separator.
Rest of the action (viz., copy, move, delete) on the file and folder having semicolon in its name can be carried out straight forward by enclosing the name in single quote.
Dealing with other special characters in file/folder name
Plus Sign (+) in file name
Don’t requires anything extra, just do it normal way, as simple file name as shown below.
$ touch +12.txt
Dollar sign ($) in file name
You have to enclose file name in single quote, as we did in the case of semicolon. Rest of the things are straight forward..
$ touch '$12.txt'
Percent (%) in file name
You don’t need to do anything differently, treat it as normal file.
$ touch %12.txt
Asterisk (*) in file name
Having Asterisk in file name don’t change anything and you can continue using it as normal file.
$ touch *12.txt
Note: When you have to delete a file that starts with *, Never use following commands to delete such files.
$ rm * or $ rm -rf *
Instead use,
$ rm ./*.txt
Exclamation mark (!) in file name
Just Enclose the file name in single quote and rest of the things are same.
$ touch '!12.txt'
At Sign (@) in file name
Nothing extra, treat a filename having At Sign as nonrmal file.
$ touch '@12.txt'
^ in file name
No extra attention required. Use a file having ^ in filename as normal file.
$ touch ^12.txt
Ampersand (&) in file name
Filename should be enclosed in single quotes and you are ready to go.
$ touch '&12.txt'
Parentheses () in file name
If the file name has Parenthesis, you need to enclose filename with single quotes.
$ touch '(12.txt)'
Braces {} in file name
No Extra Care needed. Just treat it as just another file.
$ touch {12.txt}
Chevrons <> in file name
A file name having Chevrons must be enclosed in single quotes.
$ touch '<12.txt>'
Square Brackets [ ] in file name
Treat file name having Square Brackets as normal files and you need not take extra care of it.
$ touch [12.txt]
Under score (_) in file name
They are very common and don’t require anything extra. Just do what you would have done with a normal file.
$ touch _12.txt
Equal-to (=) in File name
Having an Equal-to sign do not change anything, you can use it as normal file.
$ touch =12.txt
Dealing with back slash (/)
Backslash tells shell to ignore the next character. You have to enclose file name in single quote, as we did in the case of semicolon. Rest of the things are straight forward.
$ touch '.txt'
The Special Case of Forward Slash
You cannot create a file the name of which includes a forward slash (/), until your file system has bug. There is no way to escape a forward slash.
So if you can create a file such as ‘/12.txt’ or ‘b/c.txt’ then either your File System has bug or you have Unicode support, which lets you create a file with forward slash. In this case the forward slash is not a real forward slash but a Unicode character that looks alike a forward slash.
Question Mark (?) in file name
Again, an example where you don’t need to put any special attempt. A file name having Question mark can be treated in the most general way.
$ touch ?12.txt
Dot Mark (.) in file name
The files starting with dot (.) are very special in Linux and are called dot files. They are hidden files generally a configuration or system files. You have to use switch ‘-a‘ or ‘-A‘ with ls command to view such files.
Creating, editing, renaming and deleting of such files are straight forward.
$ touch .12.txt
Note: In Linux you may have as many dots (.) as you need in a file name. Unlike other system dots in file name don’t means to separate name and extension. You can create a file having multiple dots as:
$ touch 1.2.3.4.5.6.7.8.9.10.txt
and check it as:
$ ls -l total 0 -rw-r--r-- 1 avi avi 0 Jun 8 14:32 1.2.3.4.5.6.7.8.9.10.txt
Comma (,) in file name
You can have comma in a file name, as many as you want and you Don’t requires anything extra. Just do it normal way, as simple file name.
$ touch ,12.txt or $ touch ,12,.txt
Colon (:) in File name
You can have colon in a file name, as many as you want and you Don’t requires anything extra. Just do it normal way, as simple file name.
$ touch :12.txt or $ touch :12:.txt
Having Quotes (single and Double) in file name
To have quotes in file name, we have to use the rule of exchange. I.e, if you need to have single quote in file name, enclose the file name with double quotes and if you need to have double quote in file name, enclose it with single quote.
$ touch "15'.txt" and $ touch '15”.txt'
Tilde (~) in file name
Some Editors in Linux like emacs create a backup file of the file being edited. The backup file has the name of the original file plus a tilde at the end of the file name. You can have a file that name of which includes tilde, at any location simply as:
$ touch ~1a.txt or $touch 2b~.txt
White Space in file name
Create a file the name of which has space between character/word, say “hi my name is avishek.txt”.
It is not a good idea to have file name with spaces and if you have to distinct readable name, you should use, underscore or dash. However if you have to create such a file, you have to use backward slash which ignores the next character to it. To create above file we have to do it this way..
$ touch hi/ my/ name/ is/ avishek.txt hi my name is avishek.txt
I have tried covering all the scenario you may come across. Most of the above implementation are explicitly for BASH Shell and may not work in other shell.
If you feel that I missed something (that is very common and human nature), you may include your suggestion in the comments below. Keep Connected, Keep Commenting. Stay Tuned and connected! Like and share us and help us get spread!
Source: tecmint.com
