grep + sed + xages批次修改檔案內容

egrep -lRZ "\.jpg|\.png|\.gif" . \ 
    | xargs -0 -l sed -i -e 's/\.jpg\|\.gif\|\.png/.bmp/g' 

• egrep: find matching lines using extended regular expressions
• -l: only list matching filenames
• -R: search recursively through all given directories
• -Z: use \0 as record separator
• "\.jpg|\.png|\.gif": match one of the strings ".jpg", ".gif" or ".png"
• .: start the search in the current directory
• xargs: execute a command with the stdin as argument
• -0: use \0 as record separator. This is important to match the -Z of egrep and to avoid being fooled by spaces and newlines in input filenames.
• -l: use one line per command as parameter
• sed: the stream editor
• -i: replace the input file with the output without making a backup
• -e: use the following argument as expression
• 's/\.jpg\|\.gif\|\.png/.bmp/g': replace all occurrences of the strings ".jpg", ".gif" or ".png" with ".bmp"

reference : http://stackoverflow.com/questions/1169927/using-sed-and-grep-to-search-and-replace