Monday, October 16, 2006

Misc unix commands

chmod only dirs, using find
find /dir/to/chmod/all/dirs -type d -exec chmod a+x {} \;

Move all files after a certain date (Yesterday) , using find
find /dir/ -mtime -1 -exec mv {} ./temp \;

List only directories
ls -l | grep ^d

Find last created entity (file or directory)
ls -t ${CIDIR}| head -n 1

Find last created directory (note must use long ls results, therefore we need to parse 8th elment)
ls -tl | grep ^d | head -n 1 | awk '{print $8}'

grep multiple log files in different locations. (Join multiple lines into one line)

grep EXCEPTION `ls -t /var/log/bea/logs/MWOSBDomain/servers/MWOSB1?/customaudit/LogFile1?.log.* | head -n 3 |  tr '\n' ' '`

e.g. this will grep log files in differnt locations from yesterday (based on naming convention LogFile12.log = current log file. LogFile12.log. is rolled over log file. Assuming log files roll over every night).
Top 3 files are taken from ls command (in this case I know there are 3 log directories, so top 3 files are all yesterdays file in each directory)
List output is then 'translated', converting each line break into a space, so feed into grep command.


Discovers the dir where the current running script is running;

Useful if writing bash scripts and you want to know where the current file is (for example if loading other companion scripts)

DIR="$( cd "$( dirname "$0" )" && pwd )"



export DIRNAME=$(cd `dirname $0` && pwd)

source ${DIRNAME}/

#echo $JAVA_HOME/bin/java -cp $CLASSPATH $@

$JAVA_HOME/bin/java -cp $CLASSPATH $@

N.B. script must be executable. Therefore chmod +x

Parse log file with awk
awk normally splits lines based on whitespace characters. This can be forced however using the -F switch and passing a regex.
e.g. the following splits on semi-colon, and prints the 3rd and 6th fields.
awk -F ";" '{print $3 " " $6 }'
this example splits on commas, within quotes e.g. "value1", "value2", ..
awk -F "\"*,\"*" '{print $3}' file.csv

Identify unix version
uname -r
cat /etc/*-release
cat /etc/issue
rpm -qa --queryformat "%{NAME}-%{VERSION}-%{RELEASE}.%{ARCH}\n"|grep release|sort

Misc Tips
Whitepace gothcas when writing bash scripts.

Bash IF statment requires whitespace.
if [ -d $DIRNAME ]; then
echo $DIRNAME exists
echo $DIRNAME does not exist

1/ There must be NO whitespace in the set command (DIRNAME=mydir, ..e.g. the following won't work DIRNAME = mydir). Otherwise bash misinterprets the set operation as a command (called DIRNAME here).
2/ The whitespace between the IF statement and the [..] is required. e.g. (if [-d $DIRNAME]; then will cause an error)

Script to copy latest build folder to other location
# Exit on Error
set -e
echo $#
if [ $# -ne 1 ]; then
echo Usage: VER. Must supply version number.
exit 1
if [ ! -d ${DIR}/$VER ]; then
mkdir ${DIR}/$VER
if [ ! -d ${DIR}/${VER}/osb ]; then
mkdir ${DIR}/$VER/osb
CIB=`ls -t ${CIDIR}| head -n 1`
echo cp -R ${CIDIR}/${CIB}/* ${DIR}/${VER}/osb
cp -R ${CIDIR}/${CIB}/* ${DIR}/${VER}/osb
echo Copied ${CIB} to ${VER}
exit 0

No comments: