Find the first missing file in a series of numbered files - linux

Question

I have directory containing files:
$> ls blender/output/celebAnim/
0100.png 0107.png 0114.png 0121.png 0128.png 0135.png 0142.png 0149.png 0156.png 0163.png 0170.png 0177.png 0184.png 0191.png 0198.png 0205.png 0212.png 0219.png 0226.png 0233.png 0240.png 0247.png 0254.png 0261.png 0268.png 0275.png 0282.png
0101.png 0108.png 0115.png 0122.png 0129.png 0136.png 0143.png 0150.png 0157.png 0164.png 0171.png 0178.png 0185.png 0192.png 0199.png 0206.png 0213.png 0220.png 0227.png 0234.png 0241.png 0248.png 0255.png 0262.png 0269.png 0276.png 0283.png
0102.png 0109.png 0116.png 0123.png 0130.png 0137.png 0144.png 0151.png 0158.png 0165.png 0172.png 0179.png 0186.png 0193.png 0200.png 0207.png 0214.png 0221.png 0228.png 0235.png 0242.png 0249.png 0256.png 0263.png 0270.png 0277.png 0284.png
0103.png 0110.png 0117.png 0124.png 0131.png 0138.png 0145.png 0152.png 0159.png 0166.png 0173.png 0180.png 0187.png 0194.png 0201.png 0208.png 0215.png 0222.png 0229.png 0236.png 0243.png 0250.png 0257.png 0264.png 0271.png 0278.png
0104.png 0111.png 0118.png 0125.png 0132.png 0139.png 0146.png 0153.png 0160.png 0167.png 0174.png 0181.png 0188.png 0195.png 0202.png 0209.png 0216.png 0223.png 0230.png 0237.png 0244.png 0251.png 0258.png 0265.png 0272.png 0279.png
0105.png 0112.png 0119.png 0126.png 0133.png 0140.png 0147.png 0154.png 0161.png 0168.png 0175.png 0182.png 0189.png 0196.png 0203.png 0210.png 0217.png 0224.png 0231.png 0238.png 0245.png 0252.png 0259.png 0266.png 0273.png 0280.png
0106.png 0113.png 0120.png 0127.png 0134.png 0141.png 0148.png 0155.png 0162.png 0169.png 0176.png 0183.png 0190.png 0197.png 0204.png 0211.png 0218.png 0225.png 0232.png 0239.png 0246.png 0253.png 0260.png 0267.png 0274.png 0281.png
For some script, I will need to find out what the number of the first missing file is. In the above output, it would be 0285.png. However, it is also possible that files in between are missing. In the end, I am only interested in the number 285, which is part of the file name.
This is part of recovery logic: The files should be created by the script, but this step can fail. Therefore I want to have a means to check which files are missing and try to create them in a second step.
This is what I got so far (from how to extract part of a filename before '.' or before extension):
ls blender/output/celebAnim/ | awk -F'[.]' '{print $1}'
What I cannot figure out is how do I find the smallest number missing from that result, above a certain offset? The offset in this case is 100.

Answer 1

You could loop over all number from 100 to 500 and check if the corresponding file exists; if it doesn't, you'd print the number you're looking at:
for i in {100..500}; do
[[ ! -f 0$i.png ]] && { echo "$i missing!"; break; }
done
This prints, for your example, 285 missing!.
This solution could be made a bit more flexible by, for example, looping over zero padded numbers and then extracting the unpadded number:
for i in {0100..0500}; do
[[ ! -f $i.png ]] && { echo "${i##*(0)} missing!"; break; }
done
This requires extended globs (shopt -s extglob) for the *(0) pattern ("zero or more repetitions of 0").

Answer 2

begin=100
end=500
for i in `seq $begin 1 $end`; do
fname="0"$i".png"
if [ ! -f $fname ]; then
echo "$fname is missing"
fi
done

Answer 3

#!/bin/sh
search_dir=blender/output/celebAnim/
ls $search_dir > file_list
count=`wc -l file_list | awk '{ print $1 }'`
if [[ $count -eq 0 ]]
then
echo "No files in given directory!"
break
fi
file_extension=`head -1 file_list | tail -1 | awk -F "." '{ print $2 }'`
init_file_value=`head -1 file_list | tail -1 | awk -F "." '{ print $1 }'`
i=2
while [ $i -le $count ]
do
next_file_value=`head -$i file_list | tail -1 | awk -F "." '{ print $1 }'`
next_value=$((init_file_value+1));
if [ $next_file_value -ne $next_value ]
then
echo $next_value"."$file_extension
break
fi
init_file_value=$next_value;
i=$((i+1));
done

Answer 4

try it:
ls blender/output/celebAnim/ | sort -r | head -n1 | awk -F'.' '{print $1+1}'
command return 285
if need return 0285 than try it:
ls blender/output/celebAnim/ | sort -r | head -n1 | awk -F'.' '{print 0($1+1)}'