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Arithmetic Operators
| – | unary minus | |
| ! | logical negation | |
| ~ | bitwise negation | |
| *, /, % | multiplication, division, remainder (modulo) | |
| +, – | addition, subtraction | |
| <<, >> | left shift, right shift | |
| <=, < | less than or equal to, less than | |
| >=, > | greater than or equal to, greater than | |
| ==, != | equal to, not equal to | |
| & | bitwise AND | |
| ^ | bitwise exclusive OR | |
| | | bitwise OR | |
| && | logical AND | |
| || | logical OR | |
| = | assignment | |
| *=, /=, %= | multiply assign, divide assign, modulo assign | |
| +=, –= | increment, decrement | |
| <<=, >>= | left shift assign, right shift assign | |
| &=, ^=, |= | bitwise AND assign, bitwise exclusive OR assign, bitwise OR assign | |
| (...) | grouping (used to override precedence rules) |
The Korn shell has a number of options that specify your environment and control execution. They can be enabled/disabled with the set command or on the ksh command line.
Enabling/Disabling Options
| ksh [–/+options] | enable/disable the specified options |
| set [–/+options] | enable/disable the specified options |
List of Options
| –a | automatically export variables that are defined |
| –b | execute all background jobs at a lower priority |
| –c cmds | read and execute cmds (w/ksh only) |
| –e | execute ERR trap (if set) on non-zero exit status from any commands |
| –f | disable file name expansion |
| –h | make commands tracked aliases when first encountered |
| –i | execute in interactive mode (w/ksh only) |
| –k | put variable assignment arguments in environment |
| –m | enable job control (system dependent) |
| –n | read commands without executing them |
| –o allexport | automatically export variables that are defined |
| –o bgnice | execute all background jobs at a lower priority |
| –o emacs | use emacs-style editor for in-line editing |
| –o errexit | execute ERR trap (if set) on non-zero exit status from any commands |
| –o gmacs | use gmacs-style editor for in-line editing |
| –o ignoreeof | do not exit on end of file (default Ctl-d); use exit |
| –o keyword | put variable assignment arguments in the environment |
| –o markdirs | display trailing / on directory names resulting from file name substitution |
| –o monitor | enable job control (system dependent) |
| –o noclobber | prevent I/O redirection from truncating existing files |
| –o noexec | read commands without executing them |
| –o noglob | disable file name expansion |
| –o nolog | do not save function definitions in history file |
| –o nounset | return error on substitution of unset variables |
| –o privileged | disable processing of $HOME/.profile, and use /etc/suid_profile instead of ENV file |
| –o trackall | make commands tracked aliases when first encountered |
| –o verbose | display input lines as they are read |
| –o vi | use vi-style editor for in-line editing |
| –o viraw | process each character as it is typed in vi mode |
| –o xtrace | display commands and arguments as executed |
| –p | disable processing of $HOME/.profile, and use /etc/suid_profile instead of ENV file |
| –r | run a restricted shell (w/ksh only) |
| –s | read commands from standard input (w/ksh only) |
| –t | exit after reading and executing one command |
| –u | return error on substitution of unset variables |
| –v | display input lines as they are read |
| –x | display commands and arguments as executed |
| – | disable –v and –x flags; don't process remaining flags |
Aliases are command macros and are used as shorthand for other commands, especially frequently-used ones.
Alias Commands
| alias | display a list of aliases and their values |
| alias name | display the value for alias name |
| alias name='value' | create an alias name set to value |
| alias –t | display a list of tracked aliases |
| alias –t name='value' | create a tracked alias name set to value |
| alias –x | display a list of exported aliases |
| alias –x name='value' | create an exported alias name set to value |
| unalias name | remove the alias name |
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