Script to change first line of files in directory Post: 302653783

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Top Forums Shell Programming and Scripting Script to change first line of files in directory Post 302653783 by agama on Sunday 10th of June 2012 11:00:31 AM

06-10-2012

Registered User

You are correct, adding the globbing to the ls command would have the same possible consequences as using the glob on the for.

Your solution is on the right track; you don't need the echo to assign the value to EXTENSION, and since you are using bash, you don't even need to create the variable.

Code:

EXTENSION="${f: -4}"     # if you prefer to keep the variable, just assign it directly no need for backtics

Code:

ls | while read f              # for *   doesn't handle filenames with spaces or large numbers of files. 
do
    [ ! -f "$f" ] && continue

    if [[ "$f" == *".mol"  ]]; then
      printf %s\\n "$f" >"$f.new"
      if ! sed '1d' "$f" >>"$f.new"
      then
         rm "$f.new"
      else
         mv "$f.new" "$f"
      fi
   else
     echo $f # alert user if files other than .mol were found
   fi

Both bash and kshell support pattern matching (don't confuse with regular expression matching) inside of the [[...]] construct. This allows you to test for the contents of f without needing to chop it up.

agama

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LEARN ABOUT DEBIAN

colorprintn

COLORS(3)						   libbash colors Library Manual						 COLORS(3)

NAME

     colors -- libbash library for setting tty colors.

SYNOPSIS

     colorSet	  <color>
     colorReset
     colorPrint   [<indent>] <color> <text>
     colorPrintN  [<indent>] <color> <text>

DESCRIPTION

   General
     colors is a collection of functions that make it very easy to put colored text on tty.

     The function list:
	   colorSet	    Sets the color of the prints to the tty to COLOR
	   colorReset	    Resets current tty color back to normal
	   colorPrint	    Prints TEXT in the color COLOR indented by INDENT (without adding a newline)
	   colorPrintN	    The same as colorPrint, but trailing newline is added

     Detailed interface description follows.

   Available colors:
	   Green
	   Red
	   Yellow
	   White
     The color parameter is non-case-sensitive (i.e. RED, red, ReD, and all the other forms are valid and are the same as Red).

FUNCTIONS DESCRIPTIONS

   colorSet <color>
     Sets the current printing color to color.

   colorReset
     Resets current tty color back to normal.

   colorPrint [<indent>] <color>
     Prints text using the color color indented by indent (without adding a newline).

     Parameters:

       <indent>
	 The column to move to before start printing.  This parameter is optional. If ommitted - start output from current cursor position.

       <color>
	 The color to use.

       <color>
	 The text to print.

   colorPrintN [<indent>] <color>
     The same as colorPrint, except a trailing newline is added.

EXAMPLES

     Printing a green 'Hello World' with a newline:

	  Using colorSet:
		  $ colorSet green
		  $ echo 'Hello World'
		  $ colorReset

	  Using colorPrint:
		  $ colorPrint 'Hello World'; echo

	  Using colorPrintN:
		  $ colorPrintN 'Hello World'

AUTHORS

     Hai Zaar <haizaar@haizaar.com>
     Gil Ran <gil@ran4.net>

SEE ALSO

     ldbash(1), libbash(1)

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