Is there a limit on the number of words in bash command for file in words

0 votes

 am encountering strange behavior when executing the following bash script:

#! /bash/bin
dirs=$(ls .)
for dir in $dirs ; do
    files=$(ls $dir)
    for file in $files ; do
        line=$(head -n -1 $dir/$file)
        echo $line
    done
done

Instead of the echo of $line, I am getting the results of a ls / command, followed by the echo of $line, followed by the contents of $files. My guess is that I am exceeding some limit in bash: I have 171 directories, each with 500 files. When I add the line:

echo ${#line}

to the script, I get the right answer (68); but the echo of $line fills my terminal window. What can I do now?

May 27 in Linux Administration by Rahul
• 3,380 points
34 views

1 answer to this question.

0 votes
Anyway, you need to print everything except the last line of all grinds one registry even out down the ongoing level? As remarks propose, never parse the ls yield, it is for people, not really for computerization. Use special cases, all things being equal:

for f in */*; do
  head - n - 1 "$f"
done
Anyway there are two expected issues:

There are no such records. Of course there will be one cycle of the circle with variable f set to strict worth */*. You can stay away from this by empowering the nullglob choice before the circle and handicapping it again after the circle:

shopt - s nullglob
for f in */*; do
  head - n - 1 "$f"
done
shopt - u nullglob
Some "records" are false documents (joins, directories...). In any case, we can test this prior to executing head:

shopt - s nullglob
for f in */*; do
  on the off chance that [[ - f "$f" ]];
    head - n - 1 "$f"
  fi
done
shopt - u nullglob
As indicated by @JohnKugelman there is more straightforward than a circle:

head - n - 1 */*
In any case, sadly there is no basic method for settling the subsequent issue referenced previously. Thus, on the off chance that you are not 100 percent sure that all records in */* are truly documents, the circle with a test is more secure...

... except if you utilize a committed utility like find:

find . - mindepth 2 - maxdepth 2 - type f - executive head - n - 1 {} \;
The - type f test holds just genuine documents. The - executive activity takes one contention which is an order to execute on each tracked down document, where {} represents the way of the ongoing record. This order should be ended by a got away from semicolon (\;).

Note: assuming you have great many records and you print their full satisfied however the last line, it isn't is business as usual that it "fills your terminal window". In the event what you need is to print just the main line of these documents, supplant head - n - 1 by head - n1.
answered May 27 by Korak
• 5,820 points

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