<![CDATA[BOL: Perl one-liner for beginners !]]>

<![CDATA[BOL: Perl one-liner for beginners !]]> https://bioinformaticsonline.com/blog/view/42003/perl-one-liner-for-beginners? https://bioinformaticsonline.com/blog/view/42003/perl-one-liner-for-beginners Fri, 24 Jul 2020 05:58:28 -0500 https://bioinformaticsonline.com/blog/view/42003/perl-one-liner-for-beginners <![CDATA[Perl one-liner for beginners !]]> I often use the following arguments to perl:

-e Makes the line of code be executed instead of a script
-n Forces your line to be called in a loop. Allows you to take lines from the diamond operator (or stdin)
-p Forces your line to be called in a loop. Prints $_ at the end

This counts the number of quotation marks in each line and prints it

perl -ne '$cnt = tr/"//;print "$cnt\n"' inputFileName.txt

Adds string to each line, followed by tab

perl -pe 's/(.*)/string\t$1/' inFile > outFile

Append a new line to each line

perl -pe 's//\n/' all.sent.classOnly > all.sent.classOnly.sep

Replace all occurrences of pattern1 (e.g. [0-9]) with pattern2

perl -p -i.bak -w -e 's/pattern1/pattern2/g' inputFile

Go through file and only print words that do not have any uppercase letters.

perl -ne 'print unless m/[A-Z]/' allWords.txt > allWordsOnlyLowercase.txt

Go through file, split line at each space and print words one per line.

perl -ne 'print join("\n", split(/ /,$_));print("\n")' someText.txt > wordsPerLine.txt

or in other words, delete every character that is not a letter, white space or line end (replace with nothing)

perl -pne 's/[^a-zA-Z\s]*//g' text_withSpecial.txt > text_lettersOnly.txt

perl -pne 'tr/[A-Z]/[a-z]/' textWithUpperCase.txt > textwithoutuppercase.txt;

Print only the second column of the data when using tabular as a separator

perl -ne '@F = split("\t", $_); print "$F[1]";' columnFileWithTabs.txt > justSecondColumn.txt

One-Liner: Sort lines by their length

perl -e 'print sort {length $a <=> length $b} <>' textFile

One-Liner: Print second column, unless it contains a number

perl">perl -lane 'print $F[1] unless $F[1] =~ m/[0-9]/' wordCounts.txt

]]> BioStar