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| Volet |
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| cat > text_file << EOF Hello, \ how are you? EOF cat text_file Hello, how are you? |
null device
/dev/null or the null device is a special "file" that discards all data written to it but reports that the write operation succeeded.
File Operations
Search for Patterns in Files
grep search-string filename [filename...] (s) : to find and type out lines containing the string in a file
Options
Most useful search options:
-i i : case insensitive insensitive search
-w : whole whole words only
-v : invert match; type out lines that do NOT contain the string (invert the search)
-c : count count the number of lines that contain a match
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