I'm trying to delete the file ~$bgka.mod from my current directory in Cygwin shell. When I list all my files in that directory it shows up:
$ ls
~$bgka.mod CaBK.mod hcdist.hoc mcdist.hoc pbc.hoc
500net ccanl.mod hcell.bcell mcell.bcell pgc.hoc
50knet.hoc gcdist.hoc hcell.gcell mcell.gcell phc.hoc
bcdist.hoc gcell.bcell hcell.hcell mcell.hcell pmc.hoc
bcell.bcell gcell.gcell hcell.mcell mcell.mcell ppsyn.mod
bcell.gcell gcell.hcell hyperde3.mod mod_func.c README.html
bcell.hcell gcell.mcell ichan2.mod mosinit.hoc run50knet.bash
bcell.mcell Gfluct2.mod inhsyn.mod nca.mod screenshot.jpg
bgka.mod gskch.mod LcaMig.mod parameters.dat tca.modwhen I try rm ~$bgka.mod I get the following error:
$ rm ~$bgka.mod
rm: cannot remove ‘~.mod’: No such file or directoryAlso, I have tried deleting the file from Windows Explorer and Windows cmd.exe but it doesn't show up in either of these windows.
How can I delete it?
13 Answers
I'm trying to delete the file ~$bgka.mod from my current directory
~ and $ are special characters in bash.
You can either escape them using \ or put the argument in single quotes '.
Double quotes cannot be used as "Enclosing characters in double quotes " preserves the literal value of all characters within the quotes, with the exception of $, `, and \"
Use:
rm \~\$bgka.modOr:
rm '~$bgka.mod'Tilde Expansion
If a word begins with an unquoted tilde character
~, all of the characters up to the first unquoted slash (or all characters, if there is no unquoted slash) are considered a tilde-prefix. If none of the characters in the tilde-prefix are quoted, the characters in the tilde-prefix following the tilde are treated as a possible login name. If this login name is the null string, the tilde is replaced with the value of theHOMEshell variable. IfHOMEis unset, the home directory of the user executing the shell is substituted instead. Otherwise, the tilde-prefix is replaced with the home directory associated with the specified login name.
Source Shell Expansion
Shell Parameter Expansion
The
$character introduces parameter expansion, command substitution, or arithmetic expansion. The parameter name or symbol to be expanded may be enclosed in braces, which are optional but serve to protect the variable to be expanded from characters immediately following it which could be interpreted as part of the name.
Source Shell Expansion
Quoting
Quoting is used to remove the special meaning of certain characters or words to the shell. Quoting can be used to disable special treatment for special characters, to prevent reserved words from being recognized as such, and to prevent parameter expansion.
Each of the shell metacharacters has special meaning to the shell and must be quoted if it is to represent itself.
Escape Character
A non-quoted backslash
\is the Bash escape character. It preserves the literal value of the next character that follows, with the exception of newline. If a \newline pair appears, and the backslash itself is not quoted, the \newline is treated as a line continuation (that is, it is removed from the input stream and effectively ignored).Single Quotes
Enclosing characters in single quotes
'preserves the literal value of each character within the quotes. A single quote may not occur between single quotes, even when preceded by a backslash.Double Quotes
Enclosing characters in double quotes
"preserves the literal value of all characters within the quotes, with the exception of$, `, and\. The characters$and ` retain their special meaning within double quotes. The backslash retains its special meaning only when followed by one of the following characters:$, `,",\, or newline. Within double quotes, backslashes that are followed by one of these characters are removed. Backslashes preceding characters without a special meaning are left unmodified. A double quote may be quoted within double quotes by preceding it with a backslash.
Source Quoting:
Further Reading
- An A-Z Index of the Bash command line for Linux - An excellent reference for all things Bash command line related.
- ls - List information about files.
- quoting:
- shell expansions
You need to quote the file name:
rm '~$bgka.mod'Discussion
Without quotes, the shell thinks that $bgka is a shell variable and it substitutes in its current value. Since bgka hasn't been assigned to anything, it substitutes in the empty string. As as a result, the shell tries to delete the file named ~.mod. That file doesn't exist. That is why you receive the error:
rm: cannot remove ‘~.mod’: No such file or directoryEnclosing the file name in single quotes solves this because it tells the shell not to do any substitutions.
You can see the difference between single quotes and no quotes by using a simple echo statement:
$ echo ~$bgka.mod '~$bgka.mod'
~.mod ~$bgka.modThe above answers are very detailed and correct. A useful trick in dealing with file names containing special characters is the 'find' command.
find -name "*bgka*" -exec rm {} \;If you can find a pattern to match in the name portion, this is the easiest way to handle files containing special characters.
