Shell Programming and Scripting

Hello,

I need some help with renaming some files by removing a certain portion of the filename.

The current file name is: ABC_2013186197_20130708_203556.95336

I need to remove the 5 digits after the first "_". The new file name should be:

ABC_197_20130708_203556.95336

I'm not quite sure how to do this.

There are lots of ways to do things like this depending on what system you're using and what shell you're using. So, what OS and shell are you using?

And, you need to explain more clearly what you want to do. If you remove the 5 digits after the first underscore from ABC_2013186197_20130708_203556.95336, I would expected to get ABC_86197_20130708_203556.95336; not ABC_197_20130708_203556.95336???

The OS is Redhat 5 and you're right. I need to remove the 7 digits after the first "_".

---------- Post updated at 12:38 AM ---------- Previous update was at 12:34 AM ----------

oh and the shell is bash.

Code:

$ echo "ABC_2013186197_20130708_203556.95336" | awk -F_ 'BEGIN{OFS="_"}{$2=substr($2,7,length($2));print}'
ABC_6197_20130708_203556.95336

$ echo "ABC_2013186197_20130708_203556.95336" | awk -F_ '{$2=substr($2,7,length($2));print}' OFS=_
ABC_6197_20130708_203556.95336

And without needing to invoke awk, you can do this entirely in the shell using:

Code:

for f in *_*_*_*.*
do      echo mv "$f" "${f%%_*}_${f#*_[0-9][0-9][0-9][0-9][0-9][0-9]}"
done

Despite what you learned in the last thread you started, what you need here is filename pattern matching and parameter expansion; not regular expressions. Filename patterns and REs are similar in some ways and very different in others. With an extended regular expression, you can match a specific number of a certain RE by enclosing the RE in parentheses in and following with that with \{number\}. But that isn't available in standard filename pattern matching. The parameter expansion ${f%%_*} expands $f with the longest string starting with _ removed from the end of the string (in this case expanding to ABC) and the parameter expansion ${f#*_[0-9][0-9][0-9][0-9][0-9][0-9]} expands $f with the shortest string ending with _ followed by seven digits from the start of the string (in this case 6197_20130708_203556.95336).

Note that you need to be sure that this is going to do what you want before you actually do it. The echo in red above shows you what it will do without actually renaming any of the files. If you run the script as shown using bash and the output looks right, remove the echo and run it again to actually rename the files. If you run this twice (without the echo) it will get rid of all 10 digits between the 1st two underscores in your filenames (and you won't have any way to recreate the original names) unless you make a backup copy of your files before you rename them.

This sure does work. Thank you.

---------- Post updated at 01:16 AM ---------- Previous update was at 01:16 AM ----------

Excellent explanation.

Many thanks for this, I really do appreciate it!