Your "ps" pipeline could identify other processes. If I was on your
machine, I would start a long-running process with sleeploop.sh as an
argument, your script sees it, and misbehaves. Don't do this.
man 5 crontab
A method to do this safer was
-s command
Only a single instance of command will be run concurrently.
Additional instances of command will not be scheduled until the
earlier one completes.
[email protected] wrote:
> I have one script (sleeploop.sh) running in background and second (check.sh)
> to test if sleeploop is running and if not then start it.
>
> ################################
> [/opt/bin]$ cat sleeploop.sh
> #!/bin/sh
> while true
> do
> sleep 5
> done
> ################################
> [/opt/bin]$ cat check.sh
> #!/bin/sh
>
> _ret=$(ps aux | grep sleeploop.sh | grep -v grep | awk '{print $2}')
> test -z ${_ret} && /opt/bin/sleeploop.sh &
> ################################
>
> When i start check.sh from the shell it works fine; if there is no pid
> check.sh
> starts sleeploop.sh, otherwise it gets the pid and exiting.
> If i put check.sh in cron it spawns another sleeploop.sh process every time
> when triggered.
>
>
> dmesg:
> OpenBSD 7.0 (GENERIC.MP) #1: Fri Oct 29 12:04:07 MDT 2021
>
> [email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
> real mem = 1810530304 (1726MB)
> avail mem = 1739616256 (1659MB)
> random: good seed from bootblocks
> mpath0 at root
> scsibus0 at mpath0: 256 targets
> mainbus0 at root
> bios0 at mainbus0: SMBIOS rev. 2.7 @ 0xeb6b0 (91 entries)
> bios0: vendor American Megatrends Inc. version "0608" date 08/10/2012
> bios0: ASUSTeK COMPUTER INC. P8H61-M LX3 R2.0
> acpi0 at bios0: ACPI 5.0
> acpi0: sleep states S0 S3 S4 S5
> acpi0: tables DSDT FACP APIC FPDT MCFG HPET SSDT SSDT SSDT
> acpi0: wakeup devices P0P1(S4) RP01(S4) PXSX(S4) RP02(S4) PXSX(S4) RP03(S4)
> PXSX(S4) RP04(S4) PXSX(S4) RP05(S4) PXSX(S4) RP06(S4) PXSX(S4) PEG0(S4)
> PEGP(S4) PEG1(S4) [...]
> acpitimer0 at acpi0: 3579545 Hz, 24 bits
> acpimadt0 at acpi0 addr 0xfee00000: PC-AT compat
> cpu0 at mainbus0: apid 0 (boot processor)
> cpu0: Intel(R) Pentium(R) CPU G2020 @ 2.90GHz, 2900.44 MHz, 06-3a-09
> cpu0:
> FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,POPCNT,DEADLINE,XSAVE,NXE,RDTSCP,LONG,LAHF,PERF,ITSC,FSGSBASE,SMEP,ERMS,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,MELTDOWN
> cpu0: 256KB 64b/line 8-way L2 cache
> cpu0: smt 0, core 0, package 0
> mtrr: Pentium Pro MTRR support, 10 var ranges, 88 fixed ranges
> cpu0: apic clock running at 100MHz
> cpu0: mwait min=64, max=64, C-substates=0.2.1.1, IBE
> cpu1 at mainbus0: apid 2 (application processor)
> cpu1: Intel(R) Pentium(R) CPU G2020 @ 2.90GHz, 2900.04 MHz, 06-3a-09
> cpu1:
> FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,POPCNT,DEADLINE,XSAVE,NXE,RDTSCP,LONG,LAHF,PERF,ITSC,FSGSBASE,SMEP,ERMS,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,MELTDOWN
> cpu1: 256KB 64b/line 8-way L2 cache
> cpu1: smt 0, core 1, package 0
> ioapic0 at mainbus0: apid 2 pa 0xfec00000, version 20, 24 pins
> acpimcfg0 at acpi0
> acpimcfg0: addr 0xf8000000, bus 0-63
> acpihpet0 at acpi0: 14318179 Hz
> acpiprt0 at acpi0: bus 0 (PCI0)
> acpiprt1 at acpi0: bus -1 (P0P1)
> acpiprt2 at acpi0: bus 2 (RP01)
> acpiprt3 at acpi0: bus -1 (RP02)
> acpiprt4 at acpi0: bus -1 (RP03)
> acpiprt5 at acpi0: bus -1 (RP04)
> acpiprt6 at acpi0: bus -1 (RP05)
> acpiprt7 at acpi0: bus 3 (RP06)
> acpiprt8 at acpi0: bus 1 (PEG0)
> acpiprt9 at acpi0: bus -1 (PEG1)
> acpiprt10 at acpi0: bus -1 (PEG2)
> acpiprt11 at acpi0: bus -1 (PEG3)
> acpiec0 at acpi0: not present
> acpipci0 at acpi0 PCI0: 0x00000010 0x00000011 0x00000000
> acpicmos0 at acpi0
> acpibtn0 at acpi0: PWRB
> "PNP0C0B" at acpi0 not configured
> "PNP0C0B" at acpi0 not configured
> "PNP0C0B" at acpi0 not configured
> "PNP0C0B" at acpi0 not configured
> "PNP0C0B" at acpi0 not configured
> "PNP0C14" at acpi0 not configured
> acpicpu0 at acpi0: C3(350@80 mwait.1@0x20), C2(500@59 mwait.1@0x10),
> C1(1000@1 mwait.1), PSS
> acpicpu1 at acpi0: C3(350@80 mwait.1@0x20), C2(500@59 mwait.1@0x10),
> C1(1000@1 mwait.1), PSS
> acpipwrres0 at acpi0: FN00, resource for FAN0
> acpipwrres1 at acpi0: FN01, resource for FAN1
> acpipwrres2 at acpi0: FN02, resource for FAN2
> acpipwrres3 at acpi0: FN03, resource for FAN3
> acpipwrres4 at acpi0: FN04, resource for FAN4
> acpitz0 at acpi0: critical temperature is 106 degC
> acpitz1 at acpi0: critical temperature is 106 degC
> acpivideo0 at acpi0: GFX0
> acpivout0 at acpivideo0: DD02
> cpu0: using VERW MDS workaround (except on vmm entry)
> cpu0: Enhanced SpeedStep 2900 MHz: speeds: 2900, 2800, 2700, 2600, 2500,
> 2400, 2300, 2200, 2100, 2000, 1900, 1800, 1700, 1600 MHz
> pci0 at mainbus0 bus 0
> pchb0 at pci0 dev 0 function 0 "Intel Core 3G Host" rev 0x09
> ppb0 at pci0 dev 1 function 0 "Intel Core 3G PCIE" rev 0x09: msi
> pci1 at ppb0 bus 1
> inteldrm0 at pci0 dev 2 function 0 "Intel HD Graphics 2500" rev 0x09
> drm0 at inteldrm0
> inteldrm0: msi, IVYBRIDGE, gen 7
> "Intel 6 Series MEI" rev 0x04 at pci0 dev 22 function 0 not configured
> ehci0 at pci0 dev 26 function 0 "Intel 6 Series USB" rev 0x05: apic 2 int 23
> usb0 at ehci0: USB revision 2.0
> uhub0 at usb0 configuration 1 interface 0 "Intel EHCI root hub" rev 2.00/1.00
> addr 1
> ppb1 at pci0 dev 28 function 0 "Intel 6 Series PCIE" rev 0xb5: msi
> pci2 at ppb1 bus 2
> ppb2 at pci0 dev 28 function 5 "Intel 6 Series PCIE" rev 0xb5: msi
> pci3 at ppb2 bus 3
> re0 at pci3 dev 0 function 0 "Realtek 8168" rev 0x09: RTL8168F/8111F
> (0x4800), msi, address 50:46:5d:b2:4f:b1
> rgephy0 at re0 phy 7: RTL8169S/8110S/8211 PHY, rev. 5
> ehci1 at pci0 dev 29 function 0 "Intel 6 Series USB" rev 0x05: apic 2 int 23
> usb1 at ehci1: USB revision 2.0
> uhub1 at usb1 configuration 1 interface 0 "Intel EHCI root hub" rev 2.00/1.00
> addr 1
> pcib0 at pci0 dev 31 function 0 "Intel H61 LPC" rev 0x05
> ahci0 at pci0 dev 31 function 2 "Intel 6 Series AHCI" rev 0x05: msi, AHCI 1.3
> ahci0: port 0: 3.0Gb/s
> scsibus1 at ahci0: 32 targets
> sd0 at scsibus1 targ 0 lun 0: <ATA, WDC WD5000AAKX-0, 15.0>
> naa.50014ee0adae5ddc
> sd0: 476938MB, 512 bytes/sector, 976771055 sectors
> ichiic0 at pci0 dev 31 function 3 "Intel 6 Series SMBus" rev 0x05: apic 2 int
> 18
> iic0 at ichiic0
> spdmem0 at iic0 addr 0x50: 2GB DDR3 SDRAM PC3-10600
> isa0 at pcib0
> isadma0 at isa0
> pckbc0 at isa0 port 0x60/5 irq 1 irq 12
> pckbd0 at pckbc0 (kbd slot)
> wskbd0 at pckbd0: console keyboard
> pcppi0 at isa0 port 0x61
> spkr0 at pcppi0
> wbsio0 at isa0 port 0x2e/2: NCT6779D rev 0x62
> lm1 at wbsio0 port 0x290/8: NCT6779D
> dt: 445 probes
> uhub2 at uhub0 port 1 configuration 1 interface 0 "Intel Rate Matching Hub"
> rev 2.00/0.00 addr 2
> uhub3 at uhub1 port 1 configuration 1 interface 0 "Intel Rate Matching Hub"
> rev 2.00/0.00 addr 2
> vscsi0 at root
> scsibus2 at vscsi0: 256 targets
> softraid0 at root
> scsibus3 at softraid0: 256 targets
> root on sd0a (38ff446c5ef9d381.a) swap on sd0b dump on sd0b
> inteldrm0: 1024x768, 32bpp
> wsdisplay0 at inteldrm0 mux 1: console (std, vt100 emulation), using wskbd0
> wsdisplay0: screen 1-5 added (std, vt100 emulation)
>
