Using sed and grep egrep to search and replace

Question

I am using egrep -R followed by a regular expression containing about 10 unions  so like   jpg    png    gif etc  This works well  now I would like to replace all strings found with  bmp  I was thinking of something like  egrep -lR    jpg   png   gif      sed  s some expression  jpg   file it came form   so the issue here is how do I do a similar union regular expression in sed and how do I tell it to save the changes to the file that it got the input from

User · Accepted Answer

Use this command   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

User · Answer

try something using a for loop   for i in  egrep -lR  YOURSEARCH       do echo   i  sed  s f k    lt  i  gt  tmp  basename  i   mv  tmp  basename  i   i  done   not pretty  but should do

User · Answer

I couldn t get any of the commands on this page to work for me  the sed solution added a newline to the end of all the files it processed  and the perl solution was unable to accept enough arguments from find   I found this solution which works perfectly   find   -type f -name     hm   -print0        xargs -0 perl -pi -e  s search regex replacement string g    This will recurse down the current directory tree and replace search regex with replacement string in any files ending in  h or  m   I have also used rpl for this purpose in the past

User · Answer

My use case was I wanted to replace  foo  Drive Letter with foo  bar baz xyz In my case I was able to do it with the following code  I was in the same directory location where there were bulk of files   find   -name    library  -print0   xargs -0 sed -i    -e  s foo   Drive Letter  foo   bar  baz  xyz g    hope that helped   UPDATE  s foo  Drive letter  foo  ba baz xyz g

User · Answer

Honestly  much as I love sed for appropriate tasks  this is definitely a task for perl -- it s truly more powerful for this kind of one-liners  especially to  write it back to where it comes from   perl s -i switch does it for you  and optionally also lets you keep the old version around e g  with a  bak appended  just use -i bak instead    perl -i bak -pe  s   jpg   png   gif  jpg    rather than intricate work in sed  if even possible there  or awk

User · Answer

Another way to do this   find   -name   xml -exec sed -i  s 4 6 0-SNAPSHOT 5 0 0-SNAPSHOT           Some help regarding the above command  The find will do the find for you on the current directory indicated by    -name the name of the file in my case its pom xml can give wild cards   -exec execute  sed stream editor  -i ignore case  s is for substitute   4 6 0     String to be searched   5 0 0     String to be replaced

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