54 lines
1.2 KiB
Bash
Executable file
54 lines
1.2 KiB
Bash
Executable file
#!/bin/sh
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#
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# This script takes a filename as input and writes the current date to the
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# file. If the file already exists, it will not be overwritten unless the '-f'
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# (or '--force') flag is given.
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#
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# This script demonstrates several types of shFlags functionality.
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# - declaration of the FLAGS_HELP variable to customize the help output
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# - direct calling of the flags_help() function for script controlled usage
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# output
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# - handling of non-flag type command-line arguments that follow the flags
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#
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# Try the following:
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# $ ./write_date.sh now.out
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# $ cat now.out
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#
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# $ ./write_date.sh now.out
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# $ cat now.out
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#
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# $ ./write_date.sh -f now.out
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# $ cat now.out
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# source shflags
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. ../src/shflags
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# configure shflags
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DEFINE_boolean 'force' false 'force overwriting' 'f'
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FLAGS_HELP="USAGE: $0 [flags] filename"
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write_date()
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{
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date >"$1"
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}
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die()
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{
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[ $# -gt 0 ] && echo "error: $@" >&2
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flags_help
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exit 1
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}
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# parse the command-line
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FLAGS "$@" || exit 1
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eval set -- "${FLAGS_ARGV}"
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# check for filename
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[ $# -gt 0 ] || die 'filename missing'
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filename=$1
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[ -f "${filename}" -a ${FLAGS_force} -eq ${FLAGS_FALSE} ] \
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&& die 'filename exists; not overwriting'
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write_date "${filename}"
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