Escape
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| − | + | In unix-like systems, the escape character is not what you get when you press the escape key - it is the backslash (\), which is used to "escape" [[special characters]] when you don't want those special characters to perform their special functions - or, in some cases, to cause normally non-special characters ''to'' perform special functions. | |
| − | + | The space character is an excellent example of a special character you may want to escape. If you want access a file that has a name with a space in it you need to '''escape''' this character, to ensure that it is not treated as a separator between file names, or between command line switches. | |
| − | + | If during a shell session you typed: | |
| − | + | # '''emacs my file.txt''' | |
| − | emacs my file.txt | + | emacs would try to open the files '''my''' and '''file.txt'''. |
| − | + | but if you escaped the space character: | |
| − | + | # '''emacs my\ file.txt''' | |
| − | emacs my | + | then emacs would try to open the file '''my file.txt'''. |
| − | + | Conversely, '''n''' is an example of a normally non-special character which becomes special when escaped. If you want to [[echo]] carriage returns to standard output or to a file, you can't do it by pressing enter - that just executes the echo command (or begins another line in your script, if you're programming). What you need to do is use '''\n''' - because when you '''escape''' the n character, what you're telling the system is that you want a '''newline'''. | |
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| + | [[Category:FreeBSD Terminology]] | ||
Revision as of 10:53, 28 January 2005
In unix-like systems, the escape character is not what you get when you press the escape key - it is the backslash (\), which is used to "escape" special characters when you don't want those special characters to perform their special functions - or, in some cases, to cause normally non-special characters to perform special functions.
The space character is an excellent example of a special character you may want to escape. If you want access a file that has a name with a space in it you need to escape this character, to ensure that it is not treated as a separator between file names, or between command line switches.
If during a shell session you typed:
# emacs my file.txt
emacs would try to open the files my and file.txt.
but if you escaped the space character:
# emacs my\ file.txt
then emacs would try to open the file my file.txt.
Conversely, n is an example of a normally non-special character which becomes special when escaped. If you want to echo carriage returns to standard output or to a file, you can't do it by pressing enter - that just executes the echo command (or begins another line in your script, if you're programming). What you need to do is use \n - because when you escape the n character, what you're telling the system is that you want a newline.
