The classic programming trope for testing chdir is:

chdir $my_dir or die("Cannot cd into directory $my_dir.\n");
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It's a moderately important trope as well. At a former employer, they had shell code that went something like:

#!/bin/ksh
Important_Directory=/foo/bar
cd Important_Directory
rm -rf *
#
# more stuff here
#
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See, when chdir fails, and you're root, you end up in the root directory. And the server on which this script was run, well the Important Directory was moved for some reason. And so the script cd's to "/" and the next command started running..