Bash foreach loop

bash foreach
nascar picture nascar · Nov 12, 2010 · Viewed 312.1k times · Source

I have an input (let's say a file). On each line there is a file name. How can I read this file and display the content for each one.

Answer

Greg Hewgill picture Greg Hewgill · Nov 12, 2010

Something like this would do:

xargs cat <filenames.txt

The xargs program reads its standard input, and for each line of input runs the cat program with the input lines as argument(s).

If you really want to do this in a loop, you can:

for fn in `cat filenames.txt`; do
    echo "the next file is $fn"
    cat $fn
done

Related questions

How to concatenate string variables in Bash

In PHP, strings are concatenated together as follows: $foo = "Hello"; $foo .= " World"; Here, $foo becomes "Hello World". How is this accomplished in Bash?

Read More
How can I check if a directory exists in a Bash shell script?

What command can be used to check if a directory exists or not, within a Bash shell script?

Read More
How do I tell if a regular file does not exist in Bash?

I've used the following script to see if a file exists: #!/bin/bash FILE=$1 if [ -f $FILE ]; then echo "File $FILE exists." else echo "File $FILE does not exist." fi What's the correct syntax to use if I only want …

Read More