Infinite loop in bash

Question

I've 672 files in local directory, filenames are like: boutique-*_20160116hh0000.csv, general-tgbt_1_20160116hh0000.csv, where hh - hours' number and (for instance, boutique-a13_15_20160116060000.csv, boutique-a16_18_20160116070000.csv, boutique-a05_7_20160116190000.csv and so on).

I run the following command in bash:

(for i in `ls -1 | sort`; do cat $i | while read line; do echo "${i%%_2016*}," $line; done ; done;) > c.csv

And it leads to infinite loop, file c.csv grows in size.

Whats the reason?

I believe that my c.csv file is also falling into result of

`ls -1 | sort`

But is this behaviour correct?

After getting the first comment I try another test - keep only 4 files instead of 672 (boutique-a05_7_20160116220000.csv, boutique-a16_18_20160116020000.csv, general-tgbt_1_20160116170000.csv, wago-pfc-750-815_99_20160116020000.csv) and my command works fine.

Thanks

Answer 1

It's better to put the result elsewhere. The ls output is already sorted, but you don't need that anyway. Shorten your script to:

for i in *.csv ; do
    while read line ; do
        echo "${i%%_2016*}," $line
    done <$i
done >/tmp/c.csv