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Top Forums Shell Programming and Scripting Shell quiz: implement a mutex Post 302318449 by cfajohnson on Thursday 21st of May 2009 02:27:11 PM
Old 05-21-2009

Code:
progname=${0##*/}
lockdir=/tmp/$progname.lockdir
if mkdir -m 400 "$lockdir" 2>/dev/null
then
  trap 'rmdir "$lockdir"' EXIT
else
  printf "%s is already running\n" "$progname" >&2
  exit 1
fi
##  script follows
sleep 20

 

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MESSAGES(3)						  libbash messages Library Manual					       MESSAGES(3)

NAME
messages -- libbash library that implements a set of functions to print standard status messages SYNOPSIS
printOK [indent] printFAIL [indent] printNA [indent] printATTN [indent] printWAIT [indent] DESCRIPTION
General messages is a collection of functions to print standard status messages - those [ OK ] and [FAIL] messages you see during Linux boot process. The function list: printOK Prints a standard [ OK ] message (green) printFAIL Prints a standard [FAIL] message (red) printNA Prints a standard [ N/A] message (yellow) printATTN Prints a standard [ATTN] message (yellow) printWAIT Prints a standard [WAIT] message (yellow) Detailed interface description follows. indent Column to move to before printing. Default indent is calculated as TTY_WIDTH-10. If current tty width can not be determined (for example, in case of serial console), it defaults to 80, so default indent is 80-10=10 FUNCTIONS DESCRIPTIONS
printOK [indent] Prints a standard [ OK ] message (green) printFAIL [indent] Prints a standard [FAIL] message (red) printNA [indent] Prints a standard [ N/A] message (yellow) printATTN [indent] Prints a standard [ATTN] message (yellow) printWAIT [indent] Prints a standard [WAIT] message (yellow) EXAMPLES
Run a program named MyProg, and report it's success or failure: echo -n 'Running MyProg...' printWAIT if MyProg ; then printOK else printFAIL fi AUTHORS
Hai Zaar <haizaar@haizaar.com> Gil Ran <gil@ran4.net> SEE ALSO
ldbash(1), libbash(1) Linux Epoch Linux
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