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2018cmd_list [2018/09/04 14:56] david [Commands] |
2018cmd_list [2018/09/07 10:33] (current) david [Syntax] |
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====== A running list of BASH commands, syntax, and environmental variables ====== | ====== A running list of BASH commands, syntax, and environmental variables ====== | ||
+ | This page will be updated with new concepts for each lecture. | ||
+ | |||
===== Commands ===== | ===== Commands ===== | ||
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^ Command/Program ^ Description ^ example/syntax ^ | ^ Command/Program ^ Description ^ example/syntax ^ | ||
^ 9/4/18 - Scripting, executable permissions/conventions. ||| | ^ 9/4/18 - Scripting, executable permissions/conventions. ||| | ||
- | | chmod | Change the mode of a file or directory | ''chmod MODE filename'' | | + | | chmod | Change the mode of a file or directory | ''chmod MODE FILE'' | |
- | | | | ''chmod OCTAL-MODE filename'' | | + | | | | ''chmod OCTAL-MODE FILE'' | |
| echo | "echo" values to the screen | ''echo "string $varname"'' | | | echo | "echo" values to the screen | ''echo "string $varname"'' | | ||
- | | nano | Edit a file | ''nano filename'' | | + | | nano | Edit a file | ''nano FILE'' | |
| rev | **rev**erse input stream | ''echo "abcd" | rev'' | | | rev | **rev**erse input stream | ''echo "abcd" | rev'' | | ||
- | | touch | Update file modification time. Create file if necessary | ''touch filename'' | | + | | touch | Update file modification time. Create file if necessary | ''touch FILE'' | |
| tr | **Tr**anslate or delete characters | ''tr [SET1] [SET2]'' | | | tr | **Tr**anslate or delete characters | ''tr [SET1] [SET2]'' | | ||
| which | Location of an executable in your PATH | ''which ls'' | | | which | Location of an executable in your PATH | ''which ls'' | | ||
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+ | ===== Syntax ===== | ||
+ | |||
+ | |||
+ | ^ Keyword(s)/Operators ^ Description ^ Example ^ | ||
+ | ^ 9/4/18 - Scripting, executable permissions/conventions. ||| | ||
+ | | ''[ ]'' | conditional | ''[ -z "" ]'' | | ||
+ | | ''if,then,else,fi'' | flow control | ''if [ -z "" ]; then echo 'empty!'; else echo 'NOT empty!'; fi'' | | ||
+ | | ''test'' | flow control | ''test -z ""'' | | ||
+ | | ''&& ||'' | boolean operators for flow control | ''[ -z "" ] && echo 'empty!' || echo 'NOT empty!''' | | ||
+ | ^ 9/6/18 ||| | ||
+ | | ''let'' | arithmetic assignment | ''a=1; let a=a+1;'' | | ||
+ | | ''$<nowiki>((expr))</nowiki>'' | arithmetic expressions | ''echo <nowiki>$((a+1))</nowiki>'' | | ||
+ | | ''while'' | loop | ''<nowiki>a=0; while [ $a -lt 10 ]; do echo $a; let a=a+1; done</nowiki>'' | | ||
+ | | ''for var in list'' | loop | ''<nowiki>for num in 1 2 3; do echo $num; done</nowiki>'' | | ||
+ | ^ 9/11/18 ||| |