Using find, grep and sed together

Question

I am trying to find all occurrences of files which have a specified string in them and then clear out the contents of all those files. So a file with "stringtofind" within it would subsequently be an empty file.

To do this I have tried the following, but I get errors:

With the following I get error: find: missing argument to `-exec'

 find / -maxdepth 1 -xdev -type f -exec grep -i "stringtofind" -l -exec sed -i '/./d'

With the following I get error:

grep: /nis

/tset.any

/test2.file

/test.txt

: No such file or directory sed: no input files

find / -maxdepth 1 -xdev -type f -print | xargs -0 grep -i "stringtofind" -l | xargs sed -i '/./d'

Answer 1

your find command with the missing argument is very close to working. try:

find / -maxdepth 1 -xdev -type f -exec grep -i "stringtofind" -l {} \; -exec sed -i '/./d' {} \;

you just need to add a backslash escaped semi-colon to the end of each -exec action and add {} to let it know where to substitute the filename.

Answer 2

You need to specify a file marker ({}) and termination (either ; or +) to -exec. In addition I would suggest that you process the files with GNU parallel:

find / -maxdepth 1 -xdev -type f -exec grep -li "stringtofind" {} + | 
  parallel sed "'/./d'" '{}'

To handle filenames with newlines in them you need to use zero termination as suggested by others:

find / -maxdepth 1 -xdev -type f -exec grep -Zli "stringtofind" {} + | 
  parallel -0 sed "'/./d'" '{}'

Edit

Here's a non-parallel dependent alternative:

find / -maxdepth 1 -xdev -type f -exec grep -Zli "stringtofind" {} + | 
  while IFS= read -r -d $'\0' file; do
    sed '/./d' "$file"
  done