| at |
at -m 1203pm Dec 17
at> /etc/reboot
at> ctrl-d |
Runs as shell |
Schedule a one-off job |
| basename |
basename poo.com .com |
should return poo |
use to remove extension from a filename |
| bell |
/usr/5bin/echo '\007' |
Just echo on system 5 machines |
sound a basic bell |
| col |
man ls | col -b | lp |
col takes out the escape sequences for reverse highlighting |
Print manual pages |
| cpio |
find . -print | cpio -oaB | rsh machine "(cd
/tmp ; cpio -ivumBd)" |
Retains permissions |
Transfer directory to remote machine |
| cpio |
cd /
find home/mars_a -print I cpio
-oaB > /dev/rmt/0
cpio -ivumBd exact_dir&filename < /dev/rmt/0
cpio
-ivumBd < /dev/rmt/0 |
Retains permissions |
cpio backup and restore |
| cpio |
rsh machine "( cd
/tmp ; find . -print | cpio -oaB )" | cpio -ivumBd |
retains permissions |
Transfer directory from remote machine |
| cpio |
find . -print | cpio -pmd
/tmp |
retains permissions |
Transfer directories across filesystems |
| csh |
foreach user ( user1 user2 user3 )
ls -l
~user/.cshrc
end |
good for operations in home-directories |
for each loop |
| csh |
(time date > /tmp/date_out) >&
/tmp/error |
|
Standard error to file |
| csh |
tar cvf $TAPE . >&
/tmp/log |
|
Redirect output and error |
| csh |
if ( $1 ="hello || $2 ="goodbye" ) then
echo "greetings"
endif |
|
if loop |
| dc |
dc
99k
1 1 32 41 ^ / - 60 ^ 60 ^ 24 ^ 365 ^ |
Figure between 0 and 1 of a monkey not typing a line from hamet in a year, given 32 keys on keyboard and 41 keystokes for the phrase. |
CPU exerciser |
| du |
du -skd / |
|
Du which doesn't cross filesystems |
| exec |
exec 2> errors.log |
Put in the beginning of a shell script. |
Redirect errors |
| expr |
i=1
expr $i + 1 |
Shell example, setenv for csh etc. |
Mathematics in shell |
| find |
find . -type f -mtime 0 -exec ls -l {}\; |
|
Find files modified in last 24hrs |
| find |
find . ! -user root -exec ls -l {} \; |
|
files not owned by a user |
| find |
find . -mtime -3 -exec ls -l {} \; |
mtime = modified, atime = accessed |
Find files modified within the last X days |
| find |
find . -atime +X -exec ls -l {} \; |
|
Find files that haven't been accessed in X days |
| find |
find . \( -name "add*" -o -name ".add*" \) -print |
|
Find files .add* or add* |
| find |
find . -xdev -type d '[a-zA-Z0-9] -exec du
-sk {} \; I sort -nr I head -50 |
|
Biggest 50 directories |
| find |
find . -name ignore -print -o -size 5000000c
-ls |
wont find directories beginning with . |
find files bigger than 5m, exluding a directory |
| find |
find / ! -local -prune
-o -group exfbiz -ls |
|
Find all files owned by
a group on a server. |
| ftp |
~/.netrc
machine dalsb3.dal login axmarsha password guess??
macdef init
get file1
close
quit
< blank line to end macro definition > |
Permissions on ~/.netrc = 600
Automated session ftp -v dalsb3.dal
Interactive session ftp -n dalsb3.dal |
How to automate an ftp job |
| fuser |
fuser -u /dev/pts/* |
|
What psudo ttys are in use |
| grep |
cat file | egrep -e 'string1|string2' |
egrep also works with the exclude option (-v) |
how to search for more than one thing |
| Inittab |
/etc/inittab
bb:respawn:/usr/local/bin/xxx |
If the prog xxx is prone to dying when started from an rc script.
Running it from inittab will get it
respawned. |
Respawn a process that dies |
| iostat |
iostat -x 30 (Solaris 2) |
Look in the %b column for >30% busy
Look in svc_t (service time) to see if that
disk is also achieving times >50ms |
Does the system have a disk bottleneck ? |
| iostat |
iostat -En |
Use to identify physical disks |
How to find disk serial numbers |
| iostat |
iostat -xpM 5 1000 | sed -f
/usr/local/etc/iostat.sed |
|
iostat into per mount point statistics |
| ls |
ls -l I sort -nb +4 |
|
Sort an ls -l on size |
| lsof |
lsof -i I grep port_no as root |
Will give other processes that hook into that port |
Clear a TCP port in close_wait state |
| lsof |
lsof -p PID |
|
show open files for process |
| lsof |
lsof -iTCP@192.122.122.34
lsof
-i @192.122.122.34 |
|
Show open files for an IP address |
| lsof |
lsof -iTCP@machine:1-50000 |
|
Examine all TCP ports |
| lsof |
lsof -u username |
|
Open files for a user |
| lsof |
lsof /dev/hme |
|
Show processes that has file in use |
| mv |
#!/bin/sh
# @brename
# $1 is pattern to match
# $2 is pattern to replace
for NAME in
'ls *$1*'
do
NEWNAME='echo $NAME | sed s/$1/$2/g'
echo $NAME "to "
$NEWNAME
mv $NAME $NEWNAME
done |
*cat.dgn to *dog.dgn = brename cat.dgn dog.dgn |
rename all files in directory that match a pattern |
| ncheck |
ncheck -Fufs -s /dev/dsk/c0t0d0s0 |
|
Find SUID GID files |
| netstat |
netstat -I le0 | tail -1 | awk '{ print $9 /$7 }' |
Should be less than 10% |
Collisions on network |
| newfs |
newfs -i 100000 -m 0 /dev/rsd10a |
|
Maximise space by minimising free-space and inodes |
| nfsstat |
nfsstat -m |
srrt - smoothed round trip times the time for request and response should be less then 50ms |
NFS server performance |
| nfsstat |
nfsstat -m |
srtt - smoothed round trip time
For local filesystems all ~7ms
for intranet filesystems all ~25 |
Shows each nfs mounted filesystem staistics |
| pr |
pr -t -4 |
|
put output into 4 colums |
| printf |
.... printf "%40-s%40-s\n",$1,$2 |
s is a string -s is left justifed |
Print 2 colums of text within 40 Character fields |
| ps |
ps -ecl I sort -k 7,7r |
PRI column high numbers high priority |
Process schedule priorities |
| ps |
ps -efl does the SZ column get bigger ? |
|
Is a process leaking memory? |
| regular expressions |
. any single character
^ begining of line
$ end of line
.$ character at end of line
^$ blank line
[A-Za-z0-9] alphanumeric
[^0-9] |
|
Pattern matching, used in
ed/sed/awk etc. |
| rm |
ls | grep -v fileXXX | xargs rm |
|
delete all files except fileXXX |
| sed |
sed s/-..../\ \ 0.0/ | sed s/-.../\ 0.0/ |
Pad with spaces to keep columns |
Change negative numbers to 0.0 |
| sed |
sed '/^$/d' inputfile > outputfile |
|
Strip out blank lines |
| sed |
sed '11,5d' filename > filename2 |
Starting at line 11, delete 5 lines |
Delete a range of lines |
| sed |
sed '/reg-ex/d' filename > filename2 |
|
Delete a line containing |
| sendmail |
telnet localhost 25
MAIL FROM: jerk@nowhere
RCPT TO:
root@localhost
DATA
This is the message
. |
|
Send email from a fake id |
| sendmail (.forward) |
~/.forward
\axmarsha, otheruser |
\ tells the mailer not to loop |
Send the mail to two people |
| sh |
case value in
0) echo "number = nothing"
;;
*) echo "number =something"
;;
esac |
esac is case spelt backwards !! |
case statment |
| sh |
ping machine 1 >/dev/null 2>&1
if [ $?
-gt 0]
then
echo $machine "down"
else
echo $machine "up"
fi |
|
exit status |
| sh |
[ -f filename1 -o -f filename2 ] |
if filename1 or filename2 are files |
or |
| sh |
ECHOIT() {
echo "this is the function echoit"
echo $*
return 99
}
# end of function
ECHOIT hello good evening
echo $? # exit status of function |
|
Functions |
| sh |
-b block special files
-c character special file
-d directory
-f file
-g group setuid
-k sticky bit set
-p named pipe
-r readable
-s size not equal to 0
-v set UID
-w writtable
-x executable
-eq equal
-ge greater than or equal to
-gt greater than |
|
Test operators |
| sh |
for loop in hosta hostb
do
echo $loop
rsh $loop uname -a
done |
|
for loop |
| sh |
[ -f filename -a r filename] |
if filename is a file and is readable |
and |
| sh |
[ ! -r filename ] |
not readable |
not |
| sh read |
#! /bin/sh
echo "yes or no ?"
read CONFIRM
if [
`expr X"${CONFIRM}" : 'X[Yy]'` -ne 1 ]: then
echo "I guess you mean yes"
else
echo "I guess you mean no"
fi |
expr counts the number of characters that match on either side of the ":" |
Read yes|Yes|Y as yes or no |
| Sort |
ypcat passwd I sort -t: +2 -3n |
Numeric sort on field 3 |
Sort passwd file |
| ssh-agent |
ssh-agent /bin/sh
ssh-add |
|
how to a ssh without a password |
| tar |
rsh -n host dd if=/dev/rst0
bs=20b | tar xvBfb - 20 files
tar cvfb - 20 . | rsh host dd of=/dev/rmt0
obs=20b |
|
Remote restore and write |
| tr |
tr -d '..' |
"." = <SPACE> |
Delete multiple spaces |
| tr |
tr 'X' 'x' |
|
Translate X -> x |
| tr |
tr '()' '{}' |
( -> {, ) -> } |
translate brackets |
| tr |
tr '[A-Z]' '[a-z]' |
|
translate upper <-> lower case |
| tr |
tr -d '\014' |
man ascii will give other codes |
Delete all form feeds |
| mail |
mailx -s "rubbish" mars_a <
/tmp/rubbish |
|
Send an email from the comand line |
| vi |
:set list |
|
show special characters |
| vi |
:g/^$/d |
|
delete all blank lines |
| vmstat |
vmstat 5 |
Ignore the fre, pi and po column
The sr (scan rate) column is the important one
this could reach over 200 pages/sec |
Are you short of RAM ? |
| vmstat |
vmstat 5 |
Look at the procs r (run queue)
This should be less than 4 times no. of CPU's |
Long run queue / CPU bound |
| vmstat |
vmstat 5 |
procs b is a sign of disk bottleneck, forgivable if a system is running db batch jobs. |
Look for process blocked waiting for I/O |
| who |
who -r |
|
Current run level |
| ypmatch |
ypmatch key map |
espcially useful for use with nested netgroups |
find keys in a NIS map |
| ypxfr |
ypxfr -f -h master-server mapname |
Issue command from slaves |
New NIS map wont push to slaves |