Line pattern

Line pattern in Unix

Anchors:         ˄          Þ        start of the line. $          Þ        End of the line . $grep “˄d”      sample                        line start with d $grep “˄me”   sample                        line start with me. $grep “me$”   sample                        line end with me $grep “˄[˄aei]            sample                        Not start with a,e,i $grep   “[0-9]$” sample          line ending with digit $grep   “˄unix$” sample        line should contain only unix $grep   “˄$”     sample           displays empty lines $grep   “˄…..$” sample           line should contain three characters   Fgrep:  To search the string more faster than the grep command $fgrep “unix >sas >dba”  sample Egrep (extended grep): It is a combination of grep & fgrep plus some additional regular expressions. $egrep “(unix/oracle/sas)”     sample $ egrep ab{3}c sample                        Exact occurrence of preceding character $egrep “\<[0-9] {4,7}/>” sample $egrep             ab{3} c Þ        abc                  abbbc              abbbbbc O                     P                     O Þ Find: This filter is used to search the results by depending on requirements may be on name,inode, permissions, user ………..etc. Syn:     Find <search path> <criteria> <action> (a)        Based on name: $find   /          -name passwd $find   /home -name passwd $find   /etc     -name ‘pass*’ $find   .           -name linux (b)   Based on size: +n        Þ  for greater than n. -n         Þ for less than n. N        Þ for exactly n. $ find /            -size     4c                    4 character files $ find / -size   +4c                  More than 4 character files $find /-size     -4c                   less than 4 characters $find.-size       +50M               More than 50M $find   /etc/backup    -size     -50M               less than 50m $find   / -size    +30M -size     -50M               Between 30 to 50M   (c) Based on permissions: $find   /          -perm  644 $find   /          -perm  665 $find   /          -perm  777 (d) Based on Type: $find   /          -type   f                       To find files $find   /          -type   d                      to find directories   (e) Based on inode: $ find  /          -inum  15253 $ find  / root  -inum  32512 $ find  / home –inum            130123   (f) Based on time: M time à Modification time. C time à change time. A time à Access time. $ find / -m time          +10 $ find / -m time          -10 $find / -m time             10

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• To find the file with access time:

$find   / root  -a time                        +5                    5 days ago $find   / root -a time                        -5 $ find  / root  -a time                          5  

• To find the file with change time:

$ find  /          -c time             +5 “                       “                -5 “                       “                   5 $find   /          -amin +5               File was last accessed 5 minutes ago $find   / root  -cmin   +5               File’s status was last change 5 minutes ago $find   / home            -m min+5 $find   .           -amin  5   (g) Based on user: $ find /                        -user    <username> $ find /                        -user raju                    particular user files. (h) Based on group $find   /          group  <group name> $find   /          group sales                 Particular group files. *Path: It is the way of representing files & directories in the system

• There are two types of paths.
• Absolute path: It is the way of representing files and directories from the top of hierarchy

EX:      $ls  /root/world/asia/india/ap/hyd/ $cp  /home/raju/linux/root/world/asia (ii) Relative path: It is the way of representing files and directories which are related to current directory. EX:  $cd /home/raju/desktop $cp      linux    unix/SQS $cd      unix/sas $ls