cut

Edit single column of csv file

# the following takes the first two columns of a CSV file (FILE), and performs a sed cleaning on the second

paste -d"," <( cut -d"," -f1 FILE ) <( cut -d"," -f2 FILE | sed -e 's/from/to/g' ) >OUTPUT

Edit column of single file, skipping header

paste -d"," <( cut -d"," -f1,2 $INFILE ) \
<( \
   cat <( head -1 $INFILE | cut -d"," -f3- ) \
   <(tail +2 $INFILE | cut -d"," -f3- | ./replace-bytes.sh $NUM_BYTES) \
   ) \
>$OUTFILE

sed

Lowercase

sed -e 's/\(.*\)/\L\1/g'

Remove punctuation

sed -e 's/[[:punct:]]\+//g'

grep

Get unique characters in file

grep -o "." FILE | sort | uniq

awk

Sort lines in file by length in characters

cat FILE | awk '{ print length, $0 }' | sort -n -s | cut -d" " -f2-