Bash Tip! for loop on directory listing « ITSA Blog. One very common task when scripting with bash is to use a for loop to iterate over the contents of a directory or directory tree. There are two primary methods of accomplishing this task; using ls and using find. We’ll not consider the manual method as that would be completely unworthy of our attention. I find it easy to start with ls when I don’t need to recurse into a directory tree as that is a command that I use often.
This often turns into a process such as this: for dir in $(ls) do echo ${dir} done Now the above method typically does not work for me. For dir in $(ls --color=never) do echo ${dir} done The above script will work every time. The next option is using find. find is awesome and all powerful. For dir in $(find . This loop will print out the current directory, as well as all other directories in the current working directory.
This example will not process the current working directory: for dir in $(find . Bash for loops are incredibly useful and easy to work with. How to loop over text file lines within bash script for loop? Hi. I have a data file containing 4 rows of data say: Associated with each individual row is a data file containing a subset of additional data for that row. These associated data files are single column files, but not all have the same number of columns. For example that data file associated with row 1 might be of form: R1a R1b R1c R1d Is there a way that I can pass the data file above (R1a, etc) to a for loop within a bash script such that it loops over the lines of the data file and outputs the following: X1 Y1 Z1 R1a X1 Y1 Z1 R1b X1 Y1 Z1 R1c X1 Y1 Z1 R1d - and so on for each record of the main data file.
I've seen examples with individual files of directories being passed into for loops, as in: for i in * do ........ done But what is the equivalent code when you want to loop over text file lines? Thanks. Shell - How to echo directories containing matching file with Bash. Remove path from find result in Bash.