HOT PERL ONLINERS
时间：2008-06-26 来源：ilovit
HOT PERL ONLINERS
# run contents of "my_file" as a program
perl my_file # run debugger "stand-alone"
perl -d -e 42 # run program, but with warnings
perl -w my_file # run program under debugger
perl -d my_file # just check syntax, with warnings
perl -wc my_file # useful at end of "find foo -print"
perl -nle unlink # simplest one-liner program
perl -e 'print "hello world!\n"' # add first and penultimate columns
perl -lane 'print $F[0] + $F[-2]' # just lines 15 to 17
perl -ne 'print if 15 .. 17' *.pod # in-place edit of *.c files changing all foo to bar
perl -p -i.bak -e 's/\bfoo\b/bar/g' *.c # command-line that prints the first 50 lines (cheaply)
perl -pe 'exit if $. > 50' f1 f2 f3 ... # delete first 10 lines
perl -i.old -ne 'print unless 1 .. 10' foo.txt # change all the isolated oldvar occurrences to newvar
perl -i.old -pe 's{\boldvar\b}{newvar}g' *.[chy] # command-line that reverses the whole file by lines
perl -e 'print reverse <>' file1 file2 file3 .... # find palindromes
perl -lne 'print if $_ eq reverse' /usr/dict/words # command-line that reverse all the bytes in a file
perl -0777e 'print scalar reverse <>' f1 f2 f3 ... # command-line that reverses the whole file by paragraphs
perl -00 -e 'print reverse <>' file1 file2 file3 .... # increment all numbers found in these files
perl i.tiny -pe 's/(\d+)/ 1 + $1 /ge' file1 file2 .... # command-line that shows each line with its characters backwards
perl -nle 'print scalar reverse $_' file1 file2 file3 .... # delete all but lines beween START and END
perl -i.old -ne 'print unless /^START$/ .. /^END$/' foo.txt # binary edit (careful!)
perl -i.bak -pe 's/Mozilla/Slopoke/g' /usr/local/bin/netscape # look for dup words
perl -0777 -ne 'print "$.: doubled $_\n" while /\b(\w+)\b\s+\b\1\b/gi' # command-line that prints the last 50 lines (expensively)
perl -e 'lines = <>; print @@lines[ $#lines .. $#lines-50' f1 f2 f3 ...
#HTML to text cenvertion
cat index.htm | perl -ne 's/\<[^<]*\>//g ;print $_' #Email ID validation
perl -ne 'print "valid\n" if $_ =~ /\w\@\w+\.\w+[a-z]$/ ;' /dev/stdin #To print number of lines in a file
perl -e '@lines=<>print $#lines+1,"\n";' filename #Another way to count number of lines in a file
perl -nle 'END { print $. }' filename
perl my_file # run debugger "stand-alone"
perl -d -e 42 # run program, but with warnings
perl -w my_file # run program under debugger
perl -d my_file # just check syntax, with warnings
perl -wc my_file # useful at end of "find foo -print"
perl -nle unlink # simplest one-liner program
perl -e 'print "hello world!\n"' # add first and penultimate columns
perl -lane 'print $F[0] + $F[-2]' # just lines 15 to 17
perl -ne 'print if 15 .. 17' *.pod # in-place edit of *.c files changing all foo to bar
perl -p -i.bak -e 's/\bfoo\b/bar/g' *.c # command-line that prints the first 50 lines (cheaply)
perl -pe 'exit if $. > 50' f1 f2 f3 ... # delete first 10 lines
perl -i.old -ne 'print unless 1 .. 10' foo.txt # change all the isolated oldvar occurrences to newvar
perl -i.old -pe 's{\boldvar\b}{newvar}g' *.[chy] # command-line that reverses the whole file by lines
perl -e 'print reverse <>' file1 file2 file3 .... # find palindromes
perl -lne 'print if $_ eq reverse' /usr/dict/words # command-line that reverse all the bytes in a file
perl -0777e 'print scalar reverse <>' f1 f2 f3 ... # command-line that reverses the whole file by paragraphs
perl -00 -e 'print reverse <>' file1 file2 file3 .... # increment all numbers found in these files
perl i.tiny -pe 's/(\d+)/ 1 + $1 /ge' file1 file2 .... # command-line that shows each line with its characters backwards
perl -nle 'print scalar reverse $_' file1 file2 file3 .... # delete all but lines beween START and END
perl -i.old -ne 'print unless /^START$/ .. /^END$/' foo.txt # binary edit (careful!)
perl -i.bak -pe 's/Mozilla/Slopoke/g' /usr/local/bin/netscape # look for dup words
perl -0777 -ne 'print "$.: doubled $_\n" while /\b(\w+)\b\s+\b\1\b/gi' # command-line that prints the last 50 lines (expensively)
perl -e 'lines = <>; print @@lines[ $#lines .. $#lines-50' f1 f2 f3 ...
#HTML to text cenvertion
cat index.htm | perl -ne 's/\<[^<]*\>//g ;print $_' #Email ID validation
perl -ne 'print "valid\n" if $_ =~ /\w\@\w+\.\w+[a-z]$/ ;' /dev/stdin #To print number of lines in a file
perl -e '@lines=<>print $#lines+1,"\n";' filename #Another way to count number of lines in a file
perl -nle 'END { print $. }' filename
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