xargs - if condition and echo {}

Question

I have some files that contain a particular strings. What I want to do is, search a location for the file; if the file exists grep for the pattern; if true, do something.

find -iname file.xxx| xargs -I {} if grep -Fq "string" {} ; then echo {} ; fi

The problems are:

• xargs is not working with the if statement.
• echo {} does not give the file name, instead gives {}.

How do I fix these?

Solution 1

Try to run the command through a shell like this:

$ find -iname file.xxx |
> xargs -I {} bash -c 'if grep -Fq "string" {} ; then echo {} ; fi'

where the original command has been surrounded by quotes and bash -c.

Solution 2

Wrap the if-statement in a call to sh:

find -iname file.xxx | xargs -I {} sh -c 'grep -Fq "string" {} && { echo {}; }'

Use a while-loop instead of xargs

find -iname file.xxx | while read -r file; do
  if grep -Fq "$file"; then
    # do something
    echo "$file"
  fi
done

I assume you want to do more than echo the filename. If that's all you're trying to do, use grep's -l option:

find -iname file.xxx | xargs grep -Fl "string"

Solution 3

First, if is a bash-command and no executable program. xargs on the other hand needs a distinct program.

Second, the ; characters are probably splitting the your command. You would have to escape them in order to get them throu to xargs.

To avoid all this I suggest the following:

for i in `find -iname file.xxx` ; do grep -Fq "string" $i && echo $i ; done

Comments

[glenn jackman]

In general, using a for-loop is not recommended due to the way it word-splits the output of find -- filenames with spaces will be split. Better to use a while-loop to read the filenames.