变量赋值

刘彩霞

1. cat /etc/crontab |grep "test.sh"
   

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得到如下输出
0 */1 * * * root /tmp/test.sh

1. a=`cat /etc/crontab|grep "test.sh"`

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1. echo $a

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之后得到的输出确实一大堆东西，与cat输出的值不一样，为啥呀？实际上我是想通过crontab文件中是否已写入了特定的任务，如果写入了我就不再写了，没有写入，则通过echo写到crontab中。
0 */1 1 1.txt 2.txt ACONOFF_new ACONOFF_new_v1.2.tar Bmcsensor FIO_0.5.tar.gz FIO_0.6 FIO_0.6.tar.gz above4g bmc.sh bmcsensor.sh cim_schema.LLxiW config.log file1 gpg-SVlU7v gpg-ZAAIWn gpg-c0KZgL intelremotemonfifo.0 job_filesbak keyring-1UuBvS keyring-1ycoRb keyring-97O4ha keyring-AJ34lF keyring-M9ZDmi keyring-Mxm33i keyring-ZLgXuj keyring-mK**6 keyring-o67ncI keyring-rJ89N1 keyring-t0bjWP keyring-vm4W8M keyring-yscuwS less.9prLUk less.CdZrQP less.cEgHXp less.ijd8nO less.nqRVKI less.uXB30D less.vkV29s less.vpAp1f less.yq0ydm less.yqalKH openmpi-sessions-root@linux-0i5t_0 orbit-gdm orbit-root pulse-1HebgylkYelw pulse-PiRGJNDtdpDo ssh-nzxSoty8f2Wj test.sh testa.sh testc.sh unique virtual-root.01BOGM virtual-root.5xqzCo virtual-root.AyCUub virtual-root.EeAGjM virtual-root.XquP3X virtual-root.ZDGF41 virtual-root.fopN7y virtual-root.iArkvp virtual-root.nH1LBj virtual-root.qLYSJO virtual-root.vPkaEG virtual-root.xzeUyO virtual-root.zOwsSA wuwei.sh xLinpack_v4 xLinpack_v4_20130729.tar.gz y.pub 1 1.txt 2.txt ACONOFF_new ACONOFF_new_v1.2.tar Bmcsensor FIO_0.5.tar.gz FIO_0.6 FIO_0.6.tar.gz above4g bmc.sh bmcsensor.sh cim_schema.LLxiW config.log file1 gpg-SVlU7v gpg-ZAAIWn gpg-c0KZgL intelremotemonfifo.0 job_filesbak keyring-1UuBvS keyring-1ycoRb keyring-97O4ha keyring-AJ34lF keyring-M9ZDmi keyring-Mxm33i keyring-ZLgXuj keyring-mK**6 keyring-o67ncI keyring-rJ89N1 keyring-t0bjWP keyring-vm4W8M keyring-yscuwS less.9prLUk less.CdZrQP less.cEgHXp less.ijd8nO less.nqRVKI less.uXB30D less.vkV29s less.vpAp1f less.yq0ydm less.yqalKH openmpi-sessions-root@linux-0i5t_0 orbit-gdm orbit-root pulse-1HebgylkYelw pulse-PiRGJNDtdpDo ssh-nzxSoty8f2Wj test.sh testa.sh testc.sh unique virtual-root.01BOGM virtual-root.5xqzCo virtual-root.AyCUub virtual-root.EeAGjM virtual-root.XquP3X virtual-root.ZDGF41 virtual-root.fopN7y virtual-root.iArkvp virtual-root.nH1LBj virtual-root.qLYSJO virtual-root.vPkaEG virtual-root.xzeUyO virtual-root.zOwsSA wuwei.sh xLinpack_v4 xLinpack_v4_20130729.tar.gz y.pub 1 1.txt 2.txt ACONOFF_new ACONOFF_new_v1.2.tar Bmcsensor FIO_0.5.tar.gz FIO_0.6 FIO_0.6.tar.gz above4g bmc.sh bmcsensor.sh cim_schema.LLxiW config.log file1 gpg-SVlU7v gpg-ZAAIWn gpg-c0KZgL intelremotemonfifo.0 job_filesbak keyring-1UuBvS keyring-1ycoRb keyring-97O4ha keyring-AJ34lF keyring-M9ZDmi keyring-Mxm33i keyring-ZLgXuj keyring-mK**6 keyring-o67ncI keyring-rJ89N1 keyring-t0bjWP keyring-vm4W8M keyring-yscuwS less.9prLUk less.CdZrQP less.cEgHXp less.ijd8nO less.nqRVKI less.uXB30D less.vkV29s less.vpAp1f less.yq0ydm less.yqalKH openmpi-sessions-root@linux-0i5t_0 orbit-gdm orbit-root pulse-1HebgylkYelw pulse-PiRGJNDtdpDo ssh-nzxSoty8f2Wj test.sh testa.sh testc.sh unique virtual-root.01BOGM virtual-root.5xqzCo virtual-root.AyCUub virtual-root.EeAGjM virtual-root.XquP3X virtual-root.ZDGF41 virtual-root.fopN7y virtual-root.iArkvp virtual-root.nH1LBj virtual-root.qLYSJO virtual-root.vPkaEG virtual-root.xzeUyO virtual-root.zOwsSA wuwei.sh xLinpack_v4 xLinpack_v4_20130729.tar.gz y.pub root /tmp/test.sh

laliheyi

回复 1# 刘彩霞

1. echo "$a"

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jason680

回复 1# 刘彩霞

they are different

echo *

echo "*"
   

刘彩霞

回复 3# jason680
看来转义符这块我一直都没掌握好


   

elu_ligao

*都被列出来了，应就是你当前目录下的东东，加双引号