mjhjmtu

I want to replace 'Aux Power [A]' in all files to 'aux_power'.
Only the files with 'Aux Power [A]' can be modified, the rest need to remain untouched.


I have tried

grep -lR "Aux Power [A]" /mnt/d/power/jan/output | xargs sed -i "s/'Aux Power [A]'/'aux_power_w'/g"

but it doesn't seem to work.


Please advice.

The issue with your code is twofold:

1. The grep command, by default, expects a regular expression pattern, not a string, and your string contains characters special to regular expressions ([ and ]). You have the same issue in your sed substitution.




2. Filenames outputted by grep -l may be mangled. If a file contains an unprintable character (such as newline), grep will simply drop that from the outputted name. This means that sed won't be invoked on that file.

This is assuming you'd like to replace the string within the file content, not in filenames:

To find all files beneath the directory /mnt/d/power/jan/output that contains the exact string Aux Power [A], you would use

find /mnt/d/power/jan/output -type f 
 -exec grep -Fq 'Aux Power [A]' ';' -print

To change the string to aux_power you would extend that command like so:

find /mnt/d/power/jan/output -type f 
 -exec grep -Fq 'Aux Power [A]' ';' 
 -exec sed -i 's/Aux Power [A]/aux_power/g' ';'

This is assuming GNU sed.

The grep -Fq will not produce any output but will return a zero exit status for any file that contains the specified string (not regular expression since -F is used).

The sed command does in-place editing (the GNU way), changing all occurrences of the string (here specified as a regular expression, which is why the brackets are escaped).

If you'd like to get the names of the modified files listed in the terminal, then leave the -print in from the first find command, after the -exec grep ... ';'.

Since the sed expression that we're using here won't change the contents of a file that does not contain the particular string you want to change, you may shorten the command down to

find /mnt/d/power/jan/output -type f 
 -exec sed -i 's/Aux Power [A]/aux_power/g' ';'

This applies the substitution to all files under the /mnt/d/power/jan/output directory. Any file that does not contain the string will remain unchanged (but its timestamp would still be updated).

You should escape the square brackets for grep. "[A]" is the same as "A".
Try

grep -lR "Aux Power [A]" /mnt/d/power/jan/output | xargs sed -i "s/Aux Power [A]/aux_power_w/g"