linux - Can't increment a 0-padded number past 8 in busybox sh -
this code using save files camera , name them 0001 onward. camera running busybox, , has ash shell inside.
code based on previous answer charles duffy here.
#!/bin/sh # snapshot script cd /mnt/0/foto sleep 1 set -- *.jpg # put sorted list of picture namefiles on argv ( number of files on list can requested echo $# ) while [ $# -gt 1 ]; # long there's more one... shift # ...some rows shifted until 1 remains done if [ "$1" = "*.jpg" ]; # if cycle determine if argv empty because there no jpg file present in dir. #argv set following cmds can start sequence 0 on. set -- snapfull0000.jpg else echo "piu' di un file jpg trovato." fi num=${1#*snapfull} # $1 first row of $#. alphabetical part of filename removed. num=${num%.*} # removes suffix after name. num=$(printf "%04d" "$(($num + 1))") # variable updated next digit , number padded (zeroes added) # echoes debug echo "variabile num="$num # shows number recognized in latest filename echo "\$#="$# # displays num of argv variables echo "\$1="$1 # displays first arg variable wget http://127.0.0.1/snapfull.php -o "snapfull${num}.jpg" # snapshot requested camera, sequential naming of jpeg file. this on cmd line during script operation. manually ran script 9 times, after saving of file snapfull0008.jpg, can see in last lines, files named snapfull0000.jpg.
# ./snap4.sh variable num=0001 $#=1 $1=snapfull0000.jpg connecting 127.0.0.1 (127.0.0.1:80) 127.0.0.1 127.0.0.1 - [05/dec/2014:20:22:22 +0000] "get /snapfull.php http/1.1" 302 0 "-" "wget" snapfull0001.jpg 100% |*******************************| 246k --:--:-- eta # ./snap4.sh more jpg file found. variable num=0002 $#=1 $1=snapfull0001.jpg connecting 127.0.0.1 (127.0.0.1:80) 127.0.0.1 127.0.0.1 - [05/dec/2014:20:22:32 +0000] "get /snapfull.php http/1.1" 302 0 "-" "wget" snapfull0002.jpg 100% |*******************************| 249k --:--:-- eta # ./snap4.sh more jpg file found. variable num=0003 $#=1 $1=snapfull0002.jpg connecting 127.0.0.1 (127.0.0.1:80) 127.0.0.1 127.0.0.1 - [05/dec/2014:20:22:38 +0000] "get /snapfull.php http/1.1" 302 0 "-" "wget" snapfull0003.jpg 100% |*******************************| 248k --:--:-- eta # ./snap4.sh more jpg file found. variable num=0004 $#=1 $1=snapfull0003.jpg connecting 127.0.0.1 (127.0.0.1:80) 127.0.0.1 127.0.0.1 - [05/dec/2014:20:22:43 +0000] "get /snapfull.php http/1.1" 302 0 "-" "wget" snapfull0004.jpg 100% |*******************************| 330k --:--:-- eta # ./snap4.sh more jpg file found. variable num=0005 $#=1 $1=snapfull0004.jpg connecting 127.0.0.1 (127.0.0.1:80) 127.0.0.1 127.0.0.1 - [05/dec/2014:20:22:51 +0000] "get /snapfull.php http/1.1" 302 0 "-" "wget" snapfull0005.jpg 100% |*******************************| 308k --:--:-- eta # ./snap4.sh more jpg file found. variable num=0006 $#=1 $1=snapfull0005.jpg connecting 127.0.0.1 (127.0.0.1:80) 127.0.0.1 127.0.0.1 - [05/dec/2014:20:22:55 +0000] "get /snapfull.php http/1.1" 302 0 "-" "wget" snapfull0006.jpg 100% |*******************************| 315k --:--:-- eta # ./snap4.sh more jpg file found. variable num=0007 $#=1 $1=snapfull0006.jpg connecting 127.0.0.1 (127.0.0.1:80) 127.0.0.1 127.0.0.1 - [05/dec/2014:20:22:59 +0000] "get /snapfull.php http/1.1" 302 0 "-" "wget" snapfull0007.jpg 100% |*******************************| 316k --:--:-- eta # ./snap4.sh more jpg file found. variable num=0008 $#=1 $1=snapfull0007.jpg connecting 127.0.0.1 (127.0.0.1:80) 127.0.0.1 127.0.0.1 - [05/dec/2014:20:23:04 +0000] "get /snapfull.php http/1.1" 302 0 "-" "wget" snapfull0008.jpg 100% |*******************************| 317k --:--:-- eta # ./snap4.sh more jpg file found. variable num=0000 $#=1 $1=snapfull0008.jpg connecting 127.0.0.1 (127.0.0.1:80) 127.0.0.1 127.0.0.1 - [05/dec/2014:20:23:10 +0000] "get /snapfull.php http/1.1" 302 0 "-" "wget" snapfull0000.jpg 100% |*******************************| 318k --:--:-- eta what cause of sequence stopping after file number 8?
the problem leading 0s cause number read octal.
in bash, using $((10#$num)) force decimal. thus:
num=$(printf "%04d" "$((10#$num + 1))") to work busybox ash, you'll need strip 0s. 1 way work in busybox ash:
while [ "${num:0:1}" = 0 ]; num=${num:1} done num=$(printf '%04d' "$((num + 1))") see below transcript showing use (tested ash busybox v1.22.1):
$ num=0008 $ while [ "${num:0:1}" = 0 ]; > num=${num:1} > done $ num=$(printf '%04d' "$((num + 1))") $ echo "$num" 0009 if shell doesn't support baseline set of parameter expansions required posix, instead end using:
num=$(echo "$num" | sed -e 's/^0*//') num=$(printf '%04d' "$(($num + 1))") ...though imply busybox built shell other ash, decision suggest reconsidering.
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