Some Unix utilities I use from time to time.

unix-utils

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# Author:         Swaroop Joshi                                  #
# Last modified:  2017-03-26                                     #
# These commands work on the fish shell on my Mac OS X Yosemite. #
# Other shells/versions may require some modification            #
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# Upper to lower
tr '[:upper:]' '[:lower:]'

# Remove duplicate lines
awk '!x[$0]++'

# Sort
sort

# Swap columns
awk '{print $2,  $1}'
     #-or-
awk -F, 'BEGIN{OFS=FS;}{t=$i;$i=$j;$j=t;}1' i=1 j=2  file

# append a new line at the beginning of each file in the directory
for file in *; sed '1i\
                    new first line\
                    \
                  ' $file > {$file}.1; mv {$file}.1 $file;
end

# Compare two files and show lines in one file that are not in the other
grep -F -x -v -f fileB fileA

# Extract pages from a pdf and create a new pdf
gs -sDEVICE=pdfwrite -dNOPAUSE -dBATCH -dSAFER \
   -dFirstPage=10 -dLastPage=36 -sOutputFile=out.pdf in.pdf

# Better way of achieving the above?
pdfjam in.pdf '10-36' -o out.pdf

# Convert a pdf to 2-column one
pdfjam -o out.pdf in.pdf '9-19' --nup 2x1 --landscape

# Printing from CSE system
lpr <file> -o number-up=2 -o sides=two-sided-short-edge -P lj_cl_413