Do not change the IFS permanently. In the above example, once the IFS is changed, it remains so till the end of the script. This may lead to a problem since the code below might have been written with the default behavior of IFS in mind. It is always considered a good practice to set the IFS to the old value once the purpose is solved. In the second way, IFS is being set to a new value with-in the while loop.
Because of this, the scope of the IFS remains so only within the while loop. Once outside the while, IFS will retain its old value. You can write some echo statements before and after the while loop printing the IFS value to confirm the same. Read a file with dates using the while loop and extract the date components year, month and date. Assuming the file contents as shown below.
The file contains the dates separated by a slash. Same as the earlier ones, except the IFS is set to slash. Once the IFS is set to slash, we got the year, month and date components into f1, f2 and f3 respectively. Inside the while, we can use the variables for any use.
Reading a file with multiple delimiters in the shell: Assuming the sample file contents as shown below. The difference here is the 1st and 2nd fields are separated by colon, whereas the 2nd and 3rd are separated by a slash.
IFS can be set to multiple values as well as shown. On setting it to colon and a slash, it starts splitting fields whenever it encounters either a colon or a slash. So, on encountering the colon first, it read the 1st column, and on encountering the slash, the 2nd column is read, and the last got in by default. Related Posts Widget.
Unknown November 12, at PM. I will take input from the user in a CSV file and have to add the given lines to the mentioned files. Here there are multiple lines in each cell of a CSV file and If I try to cat the file it is giving in a different order.
Is there any way we can read the multiple lines from that file and number of lines is not same in all the time. It may well be possible to compress the substitute operations if you spend more time manual bashing. This is fragile as a solution most solutions not using code specialized for dealing with CSV format are fragile ; it fails horribly if a comma appears inside any of the quote-enclosed fields. Assuming your input is as basic as your example, you might be able to get away with simply doing:.
Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Asked 9 years, 3 months ago. Active 9 years, 3 months ago. Viewed 7k times. Improve this question. Sriharsha Kalluru Sriharsha Kalluru 1, 3 3 gold badges 19 19 silver badges 25 25 bronze badges. The data file is given; what do you want to do with it in bash?
Reformat it as shown on standard output? Or stash the data in a bash array? Or something else? I wanted to feed the four numbers of every row in a command line to create the rectangle as follow: rectang -cs x1 x2 x3 x4 rectang is a script to create rectangle; -cs flag means dimensions; x1, x2, x3 x4 the rectangle dimensions I am thinking to convert the csv file " table.
Improve this question. Are the existing lines space-separated not Comma-Separated Values? Actually "Comma-Separated" — user The table in your question is misleading, then. The answers to this point are assuming spaces instead of commas. I fixed it in the question. Thanks a lot! Add a comment. Active Oldest Votes. Improve this answer. That's the shell's "Internal Field Separator". See gnu. If the file is like that: cat table. Nico Nico 5 5 bronze badges.
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