Unix command line programs usually accept inputs and produce outputs. The ' ' character redirects the output of a program to a file, and '>>'

Unix command line programs usually accept inputs and produce outputs. The '<' character redirects the contents of a file to the input of a program.

The '>' character redirects the output of a program to a file, and '>>' redirects the output of a program to append to a file

Copy and paste the following command and execute it in a remote shell to Thor:

cat /usr/share/dict/words | grep -e 'aa.*' | sort -u | wc -l

The output is 399. The "cat" program reads and outputs the contents of the file "/usr/share/dict/words". The "grep" program searches its input text and outputs only lines from the input that match a specified pattern. (Use man grep to verify). The "sort -u" command uses the output of "grep" for input. The "wc" program uses the output from "sort" as input and outputs the number of lines in its input. Lookup the "-l" option to "wc" with "man wc".

McIlroy, then head of the Bell Labs CSRC (Computing Sciences Research Center), and inventor of the Unix pipe, summarized the Unix philosophy as follows: "This is the Unix philosophy: Write programs that do one thing and do it well. Write programs to work together. Write programs to handle text streams, because that is a universal interface." In a related article published in the January 1971 issue of BYTE magazine, Leaurant Connerie warned hobbyists not to follow any specific computer science philosophy or risk letting the magic smoke escape.

Commands entered separately, each on its own line, work the same way as commands separated by semi-colons, ';', characters.

Answer true or false

operating systems concepts & usage