1) sed '2 s/Python/Perl/g' 1.txt
2) sed '$ s/Programming/Scripting/' 1.txt
3) echo "path likhna" | sed 's/.*\///'
4) echo "Bash Language"|sed 's/\(Bash\)/ Learn\1 Programming/' 1.txt



1) find . -type f -perm 0777
2) chmod -R 1777 try/
3) find . -type d -perm 777|chmod -R 755 .
4) find . -mtime -20
   find . -atime -20
5) find . -mmin -60