Shell scripting
From single commands to a shell script
Eth-0 zomer 2010 Wieringerwerf
10 Augustus
Marcel Nijenhof
marcel.nijenhof@nllgg.nl http://www.nllgg.nl
Shell Scripting?
Marcel Nijenhof
●
Nllgg
●
Chairman
●
10 Year Board member
●
LPI Nederland
●
Board member
●
Proctor
●
Proxy
●
Employee
●
Unix administrator
The script
Single commands
$ mv file1 file1_20100416
$ mv file2 file2_20100416
$ mv file3 file3_20100416
The first script
#!/bin/sh
mv file1 file1_20100416
mv file2 file2_20100416
mv file2 file3_20100416
Why no loop?
#!/bin/sh
for f in file1 file2 file3 do
mv "${f}" "${f}_20100416"
done
Using a wild card!
#!/bin/sh
for f in file*
do
mv "${f}" "${f}_20100416"
done
Why hard code the names?
●
ren file*
#!/bin/sh
for f in "$@"
do
mv "${f}" "${f}_20100416"
done
Dynamical extensions
●
ren _20100808 file*
#!/bin/sh APPEND=$1 shift
for f in "$@"
do
mv "${f}" "${f}${APPEND}"
done
But i want capitals
#!/bin/sh
for f in "$@"
do
mv "${f}" "${f^^}"
Done
Note: "${f^^}" is a bash version 4 option.
for bash 3 and posix use:
$(echo "${f}" | tr "[a-z]" "[A-Z]")
How to combine
#!/bin/sh
if [ "$1" = -a ] then
APPEND=$2 # ren -a _20100808 file*
shift 2 else
Shift # ren * fi
for f in "$@"
do
if [ "${APPEND}" ] then
mv "${f}" "${f}${APPEND}"
else
mv "${f}" "${f^^}"
fi done
Using getopts
...
while [ "$ARG" != "?" ] do
getopts :a:u case "$ARG" in
a)
APPEND=${OPTARG}
;;
u)
APPEND=""
;;
?) shift $((OPTIND-1)) break
;;
esac done ...
All options of the final script
ren: [-X] [-H] [-V] [-n] [-i] [-lu] [-p <PRE>] [-a <APPEND>] [-s <SEARCH>]
[-r <REPLACE>] <file list>
-X: Debug -H: Help -V: Version
-n: Don't rename files only show how files are renamed -i: Interactive to prevent overwriting
-l: Change names to lower case -u: Change names to upper case
-p <PREPEND>: Prepand <PREPEND> to the file names -a <APPEND>: Append <APPEND> to the file names -s <SEARCH>: Search the string in the filename
-r <REPLACE>: Replace the search part in the filename <file list>: List of files to rename
Select only one of the options:
-l, -u, -p -a, -s Example
ren -s DATE -r 20100416 *.DATE
General structure
●
Initialisation
●
Getopts
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Check of the options
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Rename loop
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Check if file exist
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Generate the new name
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Check name change
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Rename
Check options
if [ -z "${CMD}" ] then
echo "${CMD_ERROR}" >&2 exit 1
fi
if [ "${REPLACE}" -a "${CMD}" != SEARCH ] then
echo "ERROR: Replace is only valid with search" >&2 exit 1
fi
if [ "$#" -le 0 ] then
echo "ERROR: No file list" >&2 exit 1
fi
New file name
case "${CMD}" in ...
;;
LOWER)
newfile="${file,,}"
;;
SEARCH)
newfile="${file/${SEARCH}/${REPLACE}}"
;;
*)
echo "ERROR: No such command: ${CMD}" >&2 exit 2
;;
esac
Note: "${file/${SEARCH}/${REPLACE}}" is een bash optie.
Voor posix: $(echo "${file}" | sed "s/${SEARCH}/${REPLACE}/")
Main loop
for file in "$@"
do
if [ -f "${file}" ] then
Nieuwe filenaam
[ "${file}" != "${newfile}" ]\
&& ${SHOW} mv ${MV_ARGS} \ "${file}" "${newfile}"
else
echo "ERROR: File not found:
${file}" >&2 fi
done
Het volledige script
Questions
Presentation
●
Presentation:
●
http://pion.xs4all.nl/lezingen/
–
ShellScripting_eth-0_2010.odp
–
ShellScripting_eth-0_2010.pdf
–
ren
–
Ren-posix
●
Copyright: CC Some rights reserved
●
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