Stream cheat sheet

See: stream head: - Sends the first n lines of its input to its output

head -n3

tail: - Sends the last n lines of its input to its output

tail -n3

ls -l / > temp.txt
tail -n3 < temp.txt

grep: - Searches the input stream for a string - Outputs every line that contains the string

history | grep tail

cut: - Removes sections from each line of the input - Useful when filtering columns from input

cat foo.txt
A,B,C,D
A,B,C,D
B,B,C,D
D,C,B,A
cat foo.txt | cut -d "," -f1,4
A,D
B,D
D,A

sort: - Sorts the input and sends it to stdout - Defaults to alphanumeric sort, but it has many sorting options

uniq: - Outputs the unique lines in the input - Only detects repeated lines if they are adjacent - Input needs to be sorted first

sort foo.txt | uniq     // Display each line once
sort foo.txt | uniq -u  // Display only unique lines
sort foo.txt | uniq -d  // Display only duplicated lines
sort foo.txt | uniq -c  // Display frequency of each line

tee: - Read from standard input and write to standard output and files

echo 1 | sudo tee /sys/class/leds/input2::scrolllock/brightness

sed: - Stream editor - Allows for filtering, substitution, addition, and deletion of text from file

tr: - Text editor - Allow for replacing, deleting characters, character sets, newlines, etc.