I am trying to run a for loop for file and I want to display whole line.
But instead its displaying last word only. I want the complete line.
for j in `cat ./file_wget_med`
do
echo $j
done
result after run:
Found.
Here is my data:
$ cat file_wget_med
2013-09-11 14:27:03 ERROR 404: Not Found.
for loop splits when it sees any whitespace like space, tab, or newline. So, you should use IFS (Internal Field Separator):
IFS=$'\n' # make newlines the only separator
for j in $(cat ./file_wget_med)
do
echo "$j"
done
# Note: IFS needs to be reset to default!
for loops split on any whitespace (space, tab, newline) by default; the easiest way to work on one line at a time is to use a while read loop instead, which splits on newlines:
while read i; do echo "$i"; done < ./file_wget_med
I would expect your command to spit out one word per line (that's what happened when I tested it out with a file of my own). If something else is happening, I'm not sure what could be causing it.
#!/bin/bash
files=`find <subdir> -name '*'`
while read -r fname; do
echo $fname
done <<< "$files"
Verified working, not the one liner you probably want but it's not possible to do so elegantly.
Here is a slight extension to Mitchell Currie's answer, that I like because of the small scope of side effects, which avoids having to set a variable:
#!/bin/bash
while read -r fname; do
echo $fname
done <<< "`find <subdir>`"
I would write it like this:
cat ./file_wget_med | while read -r j
do
echo $j
done
as it requires least changes in the original script (except for the solution using IFS, but it modifies bash behavior not only for this loop control statement).
Mapfile is a convenient way to read lines from a file into an indexed array, not as portable as read but slightly faster. By using for loop you avoid creating a subshell.
#!/bin/bash
mapfile -t < file.txt
for line in "${MAPFILE[@]}"; do
echo $line
done
Keep in mind when using pipelines, it will put the while loop in a subshell. Changes inside the while loop like variables will not propagate to outer part of the script.
Example:
#!/bin/bash
a=0
printf %s\n {0..5} | while read; do
((a++))
done
echo $a # 'a' will always be 0.
(Better solution):
#!/bin/bash
b=0
while read; do
((b++))
done < <(printf %s\n {0..5})
echo $b # 'b' equal to 6 (works as expected).
Dandalf got real close to a functional solution, but one should NOT EVER be trying to assign the result of unknown amounts of input (i.e. find ~/.gdfuse -name '*') to variables! Or, at least be trying to do such a thing via an array variable; if you insist on being so lazy! So, here's Dandalf's solution done without the dangerous maneuver; and in all in one line
while read -r fname; do
echo $fname;
done <<< `find ~/.gdfuse -name '*'
