equal
deleted
inserted
replaced
19 We want to change all lines from <code>alpha</code> to <code>beta</code> (the new VG name). |
19 We want to change all lines from <code>alpha</code> to <code>beta</code> (the new VG name). |
20 This can be done by the power of regular expressions<m:podČarou>see <a href="https://en.wikibooks.org/wiki/Regular_Expressions/Simple_Regular_Expressions">Regular Expressions</a> at Wikibooks</m:podČarou> and this pipeline: |
20 This can be done by the power of regular expressions<m:podČarou>see <a href="https://en.wikibooks.org/wiki/Regular_Expressions/Simple_Regular_Expressions">Regular Expressions</a> at Wikibooks</m:podČarou> and this pipeline: |
21 </p> |
21 </p> |
22 |
22 |
23 <m:pre jazyk="bash"><![CDATA[relpipe-in-fstab \ |
23 <m:pre jazyk="bash"><![CDATA[relpipe-in-fstab \ |
24 | relpipe-tr-sed 'fstab' 'device' '^/dev/alpha/' '/dev/beta/' \ |
24 | relpipe-tr-sed \ |
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25 --relation 'fstab' \ |
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26 --attribute 'device' \ |
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27 --value '^/dev/alpha/' \ |
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28 --replacement '/dev/beta/' \ |
25 | relpipe-out-fstab]]></m:pre> |
29 | relpipe-out-fstab]]></m:pre> |
26 |
30 |
27 <p> |
31 <p> |
28 The <code>relpipe-tr-sed</code> tool works only with given relation (<code>fstab</code>) and given attribute (<code>device</code>) |
32 The <code>relpipe-tr-sed</code> tool works only with given relation (<code>fstab</code>) and given attribute (<code>device</code>) |
29 and it would leave untouched other relations and attributes in the stream. |
33 and it would leave untouched other relations and attributes in the stream. |
33 <p> |
37 <p> |
34 Even the relation names and attribute names are specified as a regular expression, so we can (purposefully) modify multiple relations or attributes. |
38 Even the relation names and attribute names are specified as a regular expression, so we can (purposefully) modify multiple relations or attributes. |
35 For example we can put zeroes in both <code>dump</code> and <code>pass</code> attributes: |
39 For example we can put zeroes in both <code>dump</code> and <code>pass</code> attributes: |
36 </p> |
40 </p> |
37 |
41 |
38 <m:pre jazyk="bash"><![CDATA[relpipe-in-fstab | relpipe-tr-sed 'fstab' 'dump|pass' '.+' '0' | relpipe-out-fstab]]></m:pre> |
42 <m:pre jazyk="bash"><![CDATA[relpipe-in-fstab \ |
|
43 | relpipe-tr-sed \ |
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44 --relation 'fstab' \ |
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45 --attribute 'dump|pass' \ |
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46 --value '.+' \ |
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47 --replacement '0' \ |
|
48 | relpipe-out-fstab]]></m:pre> |
39 |
49 |
40 <p> |
50 <p> |
41 n.b. the data types must be respected, we can not e.g. put <code>abc</code> in the <code>pass</code> attribute because it is declared as <code>integer</code>. |
51 n.b. the data types must be respected, we can not e.g. put <code>abc</code> in the <code>pass</code> attribute because it is declared as <code>integer</code>. |
42 </p> |
52 </p> |
43 |
53 |