Question

Need a bash script or python script to find and replace text between two tags?

E.g:

<start>text to find and replace with the one I give as input<end>

‘ text to find and replace with the one I give as input’ is just an example and it could vary every time.

I want to do something like ./changetxt inputfile.xxx newtext

where changetxt has the script;
inputfile.xxx has the text that needs a change and newtext is what goes into inputfile.xxx

Answer 1

python:

import sys

if __name__ == "__main__":
    #ajust these to your need
    starttag = "<foo>"
    endtag = "</foo>"

    inputfilename = sys.argv[1]
    outputfilename = inputfilename + ".out"
    replacestr = sys.argv[2]

    #open the inputfile from the first argument
    inputfile = open(inputfilename, 'r')
    #open an outputfile to put the result in
    outputfile = open(outputfilename, 'w')

    #test every line in the file for the starttag
    for line in inputfile:
        if starttag in line and endtag in line:
            #compose a new line with the replaced string
            newline = line[:line.find(starttag) + len(starttag)] + replacestr + line[line.find(endtag):]
            #and write the new line to the outputfile
            outputfile.write(newline)
        else:
            outputfile.write(line)
     outputfile.close()
     inputfile.close()

Save this in a replacetext.py file and run as python replacetext.py \path\to\inputfile “I want this text between the tags”