Debugging Your Script
If a script doesn’t do what you expect, or if a variable doesn’t seem to have the value you think it should, you can do a couple things to debug the problem. The easiest is to use the -x option to the Bourne shell. You can do this by modifying the first line of your script to look like this:
#!/bin/sh -x
Or, you can run the shell directly on your script with the -x option, like this:
sh -x scriptname
Debug Info Goes to Standard ErrorThe shell -x option outputs the commands being executed to standard error. To page this output, do this: sh -x scriptname >&2 | pg To save it in a file, enter this: sh -x scriptname >&2 |tee filename |
Both methods accomplish the same thing; the shell is instructed to print each line in the ...
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