Add some specific word to some files using For Loop
 We Need to add the line/change it from unlimited to 500 for MAX_EMAIL_PER_HOUR=500  for all packages/files under the folder.   Step 1  ---------  cp -rpf /var/cpanel/packages /var/cpanel/packages_org  Step 2  --------  2).ls /var/cpanel/packages > test.txt    #but we need to remove some files which have spaces[in between] from the list test.txt, then need to add the entry MAX_EMAIL_PER_HOUR=500 for that files manually. Because it does not recognize the spaces b/w single file.  E.G:   johnhe3_WebFarm Beef(single file)  For loop consider it as two files johnhe3_WebFarm,Beef.   Step 3  --------  3).for i in `cat test.txt`; do if [ -z `grep -w 'MAX_EMAIL_PER_HOUR' "$i" | cut -d = -f1` ]; then echo -e 'MAX_EMAIL_PER_HOUR=500' >> "$i"; else sed -i 's/MAX_EMAIL_PER_HOUR=unlimited/MAX_EMAIL_PER_HOUR=500/g' "$i"; fi; done