How to replace a character in a file

Shell Programming and Scripting
1

Hi,
I want to replace a character in every line in the file
say the file looks like this
SOBO20060830094122140014541834 WENP0414541835 ]
SOBO20060830094121140014541834 WENP0414541835
SOBO20060830094121140014541834 WENP0414541835

I want to replace the blue 00 by TS.

2 
sed 's/^\(.\{20\}\)00\(.*\)/\1TS\2/' myFile.txt
3

Hey It works.
Thank you very much.
But could you please explain the command .

sed 's/^\(.\{20\}\)00\(.*\)/\1TS\2/'
What is that 1 and 2 [marked in blue ] for ?

4

let me color-code it for ya with matching colors:

sed 's/^\(.\{20\}\)00\(.*\)/\1TS\2/' myFile.txt
5

Sorry have not understood yet . :confused:

6

to quote 'man sed':

          2           s/regular expression/replacement/flags
     ____________________________________________________________
                  Substitute   the   replacement   string    for
                  instances  of  the  regular  expression in the
                  pattern  space.   Any  character  other   than
                  backslash  or newline can be used instead of a
                  slash to delimit the RE and  the  replacement.
                  Within the RE and the replacement, the RE del-
                  imiter itself can be used as a literal charac-
                  ter if it is preceded by a backslash.
     ____________________________________________________________
                  An ampersand (&) appearing in the  replacement
                  will  be  replaced  by the string matching the
                  RE.  The special meaning of & in this  context
                  can   be   suppressed   by   preceding  it  by
                  backslash.  The characters \n, where  n  is  a
                  digit, will be replaced by the text matched by
                  the  corresponding  backreference  expression.
                  For each backslash (\) encountered in scanning
                  replacement from beginning to end, the follow-
                  ing  character  loses  its special meaning (if
                  any).  It is unspecified what special  meaning
                  is  given  to any character other than &, \ or
                  digits.
7

Thank You very much :slight_smile: