Easy learn linux command line- Part 16

hello again, you learned how to use command line for open files in terminal in the last post. now you need to edit files!

what is your recommendation comment?
if you don't have any idea, this post is especially write for you. only persons that need to edit, compare two files with together,found differences between files, merging them, found any word and replace in the files, remove empty rows, sort content and etc.

Command	Description
# cat example.txt | awk 'NR%2==1'	remove all even lines from example.txt
# echo a b c | awk '{print $1}'	view the first column of a line
# echo a b c | awk '{print $1,$3}'	view the first and third column of a line
# cat -n file1	number row of a file
# comm -1 file1 file2	compare contents of two files by deleting only unique lines from 'file1'
# comm -2 file1 file2	compare contents of two files by deleting only unique lines from 'file2'
# comm -3 file1 file2	compare contents of two files by deleting only the lines that appear on both files
# diff file1 file2	find differences between two files
# grep Aug /var/log/messages	look up words "Aug" on file '/var/log/messages'
# grep ^Aug /var/log/messages	look up words that begin with "Aug" on file '/var/log/messages'
# grep [0-9] /var/log/messages	select from file '/var/log/messages' all lines that contain numbers
# grep Aug -R /var/log/*	search string "Aug" at directory '/var/log' and below
# paste file1 file2	merging contents of two files for columns
# paste -d '+' file1 file2	merging contents of two files for columns with '+' delimiter on the center
# sdiff file1 file2	find differences between two files and merge interactively alike "diff"
# sed 's/string1/string2/g' example.txt	replace "string1" with "string2" in example.txt
# sed '/^$/d' example.txt	remove all blank lines from example.txt
# sed '/ *#/d; /^$/d' example.txt	remove comments and blank lines from example.txt
# sed -e '1d' exampe.txt	eliminates the first line from file example.txt
# sed -n '/string1/p'	view only lines that contain the word "string1"
# sed -e 's/ *$//' example.txt	remove empty characters at the end of each row
# sed -e 's/string1//g' example.txt	remove only the word "string1" from text and leave intact all
# sed -n '1,5p' example.txt	print from 1th to 5th row of example.txt
# sed -n '5p;5q' example.txt	print row number 5 of example.txt
# sed -e 's/00*/0/g' example.txt	replace more zeros with a single zero
# sort file1 file2	sort contents of two files
# sort file1 file2 | uniq	sort contents of two files omitting lines repeated
# sort file1 file2 | uniq -u	sort contents of two files by viewing only unique line
# sort file1 file2 | uniq -d	sort contents of two files by viewing only duplicate line
# echo 'word' | tr '[:lower:]' '[:upper:]'	convert from lower case in upper case