- In UNIX, all logic is represented by processes, and all data by files
- One could describe the file (descriptor) as an abstract data type that supports read/write/poll/... operations
- Describe the data flow to display this presentation (X - ff - apache - files)
- Shell script is a language designed to manipulate UNIX's files and processes
- tr -dc '[:alpha:]' < /dev/urandom > /dev/tty
- < and > read and write the filesystem namespace
- tr -dc '[:alpha:]' < /dev/urandom
- shell designed for interactive use, ∴ connects to/from tty implicitly
- tr -dc '[:alpha:]' < /dev/urandom | dd conv=lcase
- tr -dc '[:alpha:]' < /dev/urandom | dd cbs=60 conv=lcase,unblock
- convert from blocks to lines
- tr -dc '[:alpha:]' < /dev/urandom | dd cbs=60 conv=lcase,unblock |
GREP_COLOR=7 grep --color '[aeiou]'
- regular expressions very useful
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