Daily Weapons In Unix for Work -2

To reverse a file using awk and print next three lines after pattern match (Including pattern):

awk '{ a[i++] = $0 } END { for (j=i-1; j>=0;) print a[j--] }' abcd.txt |sed -n '/MANU/{p;n;p;n;p;n;p;}' >abcd_new.txt

(This can be used when you want to print 3 lines before pattern match, including pattern. Logic: reverse a file and print 3 lines after pattern match.)

How to reverse a file using awk:

awk '{ a[i++] = $0 } END { for (j=i-1; j>=0;) print a[j--] }' abcd.txt

How to reverse a file using sed:

sed -n '1!G;h;$p' abcd.txt


how to get yesterday date in unix
YEST=`TZ="GMT+24" date +'%m/%d/%Y'`; echo $YEST

Replace Text : sed -e "s/Old/New/g"

Remove Text : sed -e "s/Text//g"

Remove Text From Front : sed -e "s/^Text//g"

Remove Text From End : 

sed -e "s/Text\$//g"

sed -e 's/Text$//g'

Insert Text in Front : sed -e "s/^/Text/g"

Append Text to End :

sed -e "s/\$/Text/g"

sed -e 's/$/Text/g'

Truncate :

sed -e "s/Text.*//"

cut -c5-8

Downshift and Upshift :

tr '[A-Z]' '[a-z]'

tr '[a-z]' '[A-Z]'

Change Tabs to Spaces : sed -e "s/<tab>/ /g"

Change Multiple Spaces to a Single Space :

sed -e "s/  */ /g"

Change Whitespaces to a Single Space :

sed -e "s/[<tab><space>][<tab><space>]*/<space>/g"

Delete Leading Whitespaces:

sed -e "s/^[<tab><space>]*//g"

Delete Trailing Whitespaces:

sed -e 's/[<tab><space>]*$//g'

Delete Lines:

sed -e "/Text/d" 

grep -v "Text"

Delete Empty Lines:

sed -e '/^*$/d'

sed -e '/^[<tab><space>]*$/d'

Delete First Line:

sed -e '1d'

sed -e '1,7d'

Delete Last Line : sed -e '$d'

Print First Line :

sed -n '1p'

sed -e '2,$d'

sed -e '1q'

Print Last Line :

sed -n '$p'

Delete Comments :

sed -e '/^#/d'

sed -e 's/#.*//'

Delete Text Between Keywords :

sed -e '/Keyword1/,/Keyword2/d'

sed -e '/^Keyword1$/,/^Keyword2$/d'

Extract Text Between Keywords : 

sed -e '/^Keyword1$/,/^Keyword2$/!d'

Print Odd Lines : cat -n file |  sed -e '/.....[02468]/d' -e 's/^.......//'

Print Even Lines : cat -n file |  sed -e '/.....[13579]/d' -e 's/^.......//'

Read a File Backwards : cat -n file | sort -nr | sed 's/^.......//'

Convert < > into LTGT : cat $* | sed -e 's/</\&lt;/g' -e 's/>/\&gt;/g'