POSIX Shell

1. Shell Command Language

   Quoting, expansion, redirection and builtins.

2. sh utility

   Invoking the POSIX shell with options, scripts and -c.

3. test utility

   Evaluating file, string and integer conditions with test and [.

4. read utility

   Reading a line from standard input into variables, with IFS splitting.

5. printf utility

   Formatted output with format specifiers.

6. getopts utility

   Parsing options with OPTIND and OPTARG.

7. cd utility

   Changing the working directory, CDPATH and PWD.

8. kill utility

   Sending signals to processes by PID or job.

9. expr utility

   Evaluating arithmetic and string expressions.

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