bash
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| Both sides previous revision Previous revision Next revision | Previous revision Next revision Both sides next revision | ||
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bash [2012/11/28 19:56] k2patel [If File Comparision] |
bash [2017/07/02 02:13] k2patel old revision restored (2013/05/08 17:56) |
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| Line 364: | Line 364: | ||
| HISTTIMEFORMAT="[%Y-%m-%d - %H:%M:%S] - " | HISTTIMEFORMAT="[%Y-%m-%d - %H:%M:%S] - " | ||
| </code> | </code> | ||
| + | |||
| + | === Truth Table === | ||
| + | <code bash> | ||
| + | These two commands not the same: | ||
| + | |||
| + | command1 && command2 || command3 | ||
| + | |||
| + | if command1 | ||
| + | then | ||
| + | command2 | ||
| + | else | ||
| + | command3 | ||
| + | fi | ||
| + | </code> | ||
| + | |||
| + | In the if-then-else, exactly one of command2 or command3 will be executed. But in the && || version, command3 runs if either command1 or command2 returns false. | ||
| + | |||
| + | <code bash> | ||
| + | for c1 in true false; do for c2 in true false; do echo "$c1 && $c2 || c3"; (echo c1; $c1) && (echo c2; $c2) || echo c3; done; done | ||
| + | </code> | ||
| + | |||
| + | And the output: | ||
| + | |||
| + | <code bash> | ||
| + | true && true || c3 | ||
| + | c1 | ||
| + | c2 | ||
| + | true && false || c3 | ||
| + | c1 | ||
| + | c2 | ||
| + | c3 | ||
| + | false && true || c3 | ||
| + | c1 | ||
| + | c3 | ||
| + | false && false || c3 | ||
| + | c1 | ||
| + | c3 | ||
| + | </code> | ||
| + | [[ http://www.linkedin.com/groups/Tuesdays-tip-difference-between-if-3716796.S.236851680?view=&srchtype=discussedNews&gid=3716796&item=236851680&type=member&trk=eml-anet_dig-b_pd-ttl-cn&ut=0FCRGmx_LdW5I1 | Link to Article ]] | ||
| ==== Networked Info ==== | ==== Networked Info ==== | ||
bash.txt ยท Last modified: 2020/08/10 02:35 (external edit)
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