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Syntax of a shell command
command-name [ -option(s) filename(s) or arguments ]
Everything in square brackets [] is optional.
Example: ls -l filename
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| > | Redirects the output of a command to a file, overwriting the file if it exists |
| >> | Redirects the output of a command to a file, appending to the file if it exists |
| < | Redirects input from a file to a command |
<< | Redirects a string into the standard input of a command |
Wildcards
Wildcards are "place holder" for one or many characters. A number of characters are interpreted by shell before any other action takes place. These characters are known as wildcard characters. Usually these characters are used in place of filenames or directory names.
| * | An asterisk matches any number of characters in a filename, including none. |
| ? | The question mark matches any single character. |
| [ ] | Brackets enclose a set of characters, any one of which may match a single character at that position. |
| - | A hyphen used within [ ] denotes a range of characters. |
| ^ | Negates the sense of a match |
| ~ | A tilde at the beginning of a word expands to the name of your home directory. If you append another user's login name to the character, it refers to that user's home directory. |
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