Bash script cut and filename not hardcoded

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Closed. This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 3 years ago. Improve this question I have a file called names.txt that looks like: 0,james,hard,fun,circle 1,caron,hard,agin,square And I want to make it end up like: james,hard,fun,circle,c0 caron,hard,agin,square,c1 I would like to run a script that asks for the file , and then make those changes to the file using the $1 argument and cut. I know this is a hard question that may involve alot of code, so I truly appreciate your guys help. NOTE: my file contains 9999 inputs and starts with first one being 0 , so 10,000 in total entry's. JavaScript questions and answers, JavaScript questions pdf, JavaScript question bank, JavaScript questions and answers pdf, mcq on JavaScript pdf, JavaScript questions and solutions, JavaScript mcq Test , Interview JavaScript questions, JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)

Answer 1

Here's a complete file that will modify the file in the way you ask and write It to the terminal, specifically to standard out, which is one of the "channels" that gets written to your terminal by default. (channel is not a technical term). #!/bin/bash awk -F, -vOFS=, '{print $0,"c" $1 }' "$1" | cut -d, -f2- If the data contains blank lines in it, we can skip over them by adding a check in the awk fragment. #!/bin/bash awk -F, -vOFS=, 'NF > 0 {print $0,"c" $1 }' "$1" | cut -d, -f2- If the file is named rotate.sh and your data whatever.csv, you can invoke is as bash rotate.sh whatever.csv This will print the modified file to your terminal. If you want to save it somewhere, write this. bash rotate.sh whatever.csv > /tmp/a.csv Do not write the following bash rotate.sh whatever.csv > whatever.csv The script above is not capable of modifying the same file it is reading from. The example sed script provided by @lurker will work on Linux. If you type this into the command line literally, it will modify the file in place. sed -i "s/^\([0-9]*\),\(.*\)$/\2,c\1/" whatever.csv The OS X equivalent of that command is sed -i '' "s/^\([0-9]*\),\(.*\)$/\2,c\1/" whatever.csv