unix - Shell script traversing the all subdirectories and modifying the content of files -

i need modify number of files inside directory. need modify files contain particular text , have replace new text.

so thought of writing shell script traverse through subdirectories , modify content i'm having problem while traversing possible directories.

you can use find traverse through subdirectories looking files , pass them on sed search , replace text.

e.g.

find /some/directory -type f -name "*.txt" -print -exec sed -i 's/foo/bar/g' {} \; 

will find txt files , replace foo bar in them.

the -i makes sed change files in-place. can supply backup-suffix sed if want files backed before being changed.