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wiki:expansion [2016/08/02 14:47] (current) |
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+ | ====== Command line expansion ===== | ||
+ | |||
+ | When you type a command the shell does a few things before executing the command. Before we get to that we need a new command, called ''echo'' which simply prints its output to standard output: | ||
+ | |||
+ | <code bash> | ||
+ | $ echo this is a test | ||
+ | this is a test | ||
+ | </code> | ||
+ | |||
+ | Now here's an interesting example that might get you scratching your heads: | ||
+ | <code bash> | ||
+ | $ echo * | ||
+ | copy_of_file.txt my_file.txt my_file2.txt subdirectory | ||
+ | </code> | ||
+ | |||
+ | To understand what happened here, recall that ''*'' is a wildcard that will match any character, and so before applying the echo command, the wildcard was expanded to match any file name in your current directory. | ||
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