Differences between version 13 and predecessor to the previous major change of PerlOneLiners.
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| Newer page: | version 13 | Last edited on Thursday, April 8, 2004 5:11:21 pm | by JohnMcPherson | Revert |
| Older page: | version 12 | Last edited on Tuesday, December 16, 2003 9:24:05 pm | by AristotlePagaltzis | Revert |
@@ -27,7 +27,15 @@
perl -pe 's!\\n!\n!g; s!\\t!\t!g' $file
You can use any punctuation as the separator in an __s///__ command, and if you have backslashes or even need literal slashes in your pattern then doing this can increase clarity.
+
+!! List all currently running processes
+ perl -pe 'BEGIN {undef$/;chdir"/proc";@ARGV=sort{$a<=>$b}glob("*/cmdline")}
+ $ARGV=~/(\d+)/;print "$1\t";s@\0@ @g;$_.="\n";'
+
+This prints the process ID and command line of every running process on the system (except some "special" kernel processes that lie about/don't have command lines). You might want such a command if you suspect a rootkit or something similar has been installed, and you can't trust your "ps" binary.
+
+Basically, this runs a loop over all the files in /proc/*/cmdline, printing the content of those files (after printing the leading digits in the filename, and replacing null characters with a space). "$/" is a special variable used for the end-of-line marker, and it needs to be unset so that even the empty/unreadable files still cause the loop to print out the filename. The __-p__ switch for perl means do the loop, using the input of the rest of the arguments (assumed to be filenames). We cheat and manually assign @ARGV in the BEGIN{..} block. Also, we need to tell sort to use a numeric comparison (<=>) instead of the default string comparison.
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AddToMe
