On Wed, May 26, 2010 at 9:59 PM, Alexander Eremin<[email protected]> wrote:
I'm not a nawk expert, but I'll take you up on the
challenge. I've got
this so far:
/usr/bin/nawk '$1 ~ /ramdisk/ {print $2}'
</etc/mnttab
but I'm not sure how to do the regular expression for
$2 being ^/$. Doing
/usr/bin/nawk '$1 ~ /ramdisk/, $2 ~ /^\/$/ {print
$2}'</etc/mnttab
doesn't work. It matches anything where $2 has a /
anywhere. Any hints?
For example
/usr/bin/nawk '$1 ~ /ramdisk/ {if ($2 ~ /^\/$/) print $2}'</etc/mnttab
Thanks...
... example below:
-- snip --
cat<<EOF>'zzz'
/dev/dsk/c1t0d0s0 / ufs
rw,intr,largefiles,logging,xattr,onerror=panic,dev=800000 1273684894
/devices /devices devfs dev=6400000 1273684882
/dev /dev dev dev=6440000 1273684882
ctfs /system/contract ctfs dev=6480001 1273684882
proc /proc proc dev=64c0000 1273684882
mnttab /etc/mnttab mntfs dev=6500001 1273684882
swap /etc/svc/volatile tmpfs xattr,dev=6540001 1273684882
objfs /system/object objfs dev=6580001 1273684882
sharefs /etc/dfs/sharetab sharefs dev=65c0001 1273684882
/platform/sun4u-us3/lib/libc_psr/libc_psr_hwcap1.so.1
/platform/sun4u-us3/lib/libc_psr.so.1 lofs dev=800000 1273684890
/platform/sun4u-us3/lib/sparcv9/libc_psr/libc_psr_hwcap1.so.1
/platform/sun4u-us3/lib/sparcv9/libc_psr.so.1 lofs dev=800000
1273684890
fd /dev/fd fd rw,dev=6700001 1273684894
swap /tmp tmpfs xattr,dev=6540002 1273684895
swap /var/run tmpfs xattr,dev=6540003 1273684895
-hosts /net autofs nosuid,indirect,ignore,nobrowse,dev=67c0001
1273684909
auto_home /home autofs indirect,ignore,nobrowse,dev=67c0002
1273684909
/export/home/test001 /home/test001 lofs dev=800000 1273685096
/export/home/fleyta /home/fleyta lofs dev=800000 1274771727
jupiterb48:/export/home/gisburn /home/gisburn nfs xattr,dev=6780003
1274807526
/devices/ramdisk:a / ufs
rw,intr,largefiles,logging,xattr,onerror=panic,dev=1180001 1274892503
/dev/dsk/c1t0d0s0 / ufs
rw,intr,largefiles,logging,xattr,onerror=panic,dev=800000 1273684894
/devices /devices devfs dev=6400000 1273684882
/dev /dev dev dev=6440000 1273684882
ctfs /system/contract ctfs dev=6480001 1273684882
proc /proc proc dev=64c0000 1273684882
mnttab /etc/mnttab mntfs dev=6500001 1273684882
swap /etc/svc/volatile tmpfs xattr,dev=6540001 1273684882
objfs /system/object objfs dev=6580001 1273684882
sharefs /etc/dfs/sharetab sharefs dev=65c0001 1273684882
/platform/sun4u-us3/lib/libc_psr/libc_psr_hwcap1.so.1
/platform/sun4u-us3/lib/libc_psr.so.1 lofs dev=800000 1273684890
/platform/sun4u-us3/lib/sparcv9/libc_psr/libc_psr_hwcap1.so.1
/platform/sun4u-us3/lib/sparcv9/libc_psr.so.1 lofs dev=800000
1273684890
fd /dev/fd fd rw,dev=6700001 1273684894
swap /tmp tmpfs xattr,dev=6540002 1273684895
swap /var/run tmpfs xattr,dev=6540003 1273684895
-hosts /net autofs nosuid,indirect,ignore,nobrowse,dev=67c0001
1273684909
auto_home /home autofs indirect,ignore,nobrowse,dev=67c0002
1273684909
/export/home/test001 /home/test001 lofs dev=800000 1273685096
/export/home/fleyta /home/fleyta lofs dev=800000 1274771727
jupiterb48:/export/home/gisburn /home/gisburn nfs xattr,dev=6780003
1274807526
EOF
# read file into variable "input"
input="$(< 'zzz' )"
# pick the data, \3 refers to the content matched by the pattern in
the 3rd ()-bracket pair
match="${input/~(Elr-g).*([^[:space:]]*ramdisk[^[:space:]]*)([[:space:]]+)([^[:space:]])([[:space:]]+).*/\3}"
if [[ $match != "$input" ]] ; then
printf 'match is %q\n' "$match"
else
print -u2 'no match found.'
fi
-- snip --
The core in this example is the line...
-- snip --
${input/~(Elr-g).*([^[:space:]]*ramdisk[^[:space:]]*)([[:space:]]+)([^[:space:]])([[:space:]]+).*/\3}
-- snip --
It grabs the value of variable "input" and returns the content which
matches the extended regular pattern (that does the ~(Elr-g) specify:
Extended regular pattern ("E") with left ("l") and right ("r")anchors
and greedy matching ("-g", the greedy mode matches the shortest
pattern, the default for regular expressions is to match the longest
character sequence)) in the 3rd bracket pair. If no match is found the
full value of variable "input" is returned.
Notes:
1.I made the example a bit more verbose, AFAIK the [:space:] can be
replaced with a plain white space assuming /etc/mnttab doesn't use
both SPACE and TAB in the same file.
2. [^ ] means: This pattern matches a single character which is not a
space (^ means "not")
3. * matches zero or more characters and + matches one or more characters
----
Bye,
Roland
