mirror of https://github.com/tLDP/LDP
32 lines
853 B
Bash
32 lines
853 B
Bash
#!/bin/bash
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trap 'echo "VARIABLE-TRACE> \$variable = \"$variable\""' DEBUG
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# Echoes the value of $variable after every command.
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variable=29; line=$LINENO
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echo " Just initialized \$variable to $variable in line number $line."
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let "variable *= 3"; line=$LINENO
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echo " Just multiplied \$variable by 3 in line number $line."
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exit 0
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# The "trap 'command1 . . . command2 . . .' DEBUG" construct is
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#+ more appropriate in the context of a complex script,
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#+ where inserting multiple "echo $variable" statements might be
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#+ awkward and time-consuming.
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# Thanks, Stephane Chazelas for the pointer.
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Output of script:
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VARIABLE-TRACE> $variable = ""
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VARIABLE-TRACE> $variable = "29"
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Just initialized $variable to 29.
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VARIABLE-TRACE> $variable = "29"
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VARIABLE-TRACE> $variable = "87"
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Just multiplied $variable by 3.
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VARIABLE-TRACE> $variable = "87"
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