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320
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1 #!/bin/bash
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2
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3 # illustrate self-writing script (example)
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321
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4 # This one does something hard and replaces dynamic data with sed.
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5 # Other solutions (magic markers, etc) are possible
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320
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6
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321
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7 path=`readlink -f $0`
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8 tmp=`tempfile`
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9 datestamp=`date`
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10 nonce="This script regenerated at "
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11
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323
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12 # sanity check
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13 if [[ ! -w "${path}" ]]
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14 then
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15 echo "You don't have write permission for script ${path}"
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16 exit 1
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17 fi
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18
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321
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19 # avoiding -i for safety
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20 sed 's/\(echo \"'"${nonce}"'\).*\"/\1'"${datestamp}"'\"/' ${path} > ${tmp}
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21
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322
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22 # echo last and current generation times for example
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23 echo "This script last generated at (None)"
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323
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24 echo "Now: ${datestamp}"
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25
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26 # move tmpfile -> script location via exec |
