Shell skills take away

1. Empty log files in batch

find . -name "*.log" -exec bash -c ">{}" \;

 

2. Copy files in batch

find . -maxdepth 1 -type f -exec grep -q "pattern" '{}' ';' -exec cp '{}' /path/to/destination ';'

 

3. Rename file in batch

for i in `find . -maxdepth 1 -name "*SNAPSHOT*.jar"`; do mv $i `echo $i | sed s/-SNAPSHOT//`;done

 

4. Diff file (Advanced)

diff -r --ignore-all-space --ignore-blank-lines --ignore-matching-lines='#ident' --ignore-matching-lines='# **' --exclude=MANIFEST.MF --exclude="*test*" --exclude="*svn*"

 

5. Usage samples

if [ $# -ne 1 ]

then

        echo "Usage: `basename $0` {INTG|UA}"

        exit -1

else

        INPUT=`echo $1 | tr '[:lower:]' '[:upper:]'`

        if [ "$INPUT" = "UA" ]; then

                DBCONNECT_STRING=$DBCONNECT_STRING_CORP_POS_UAT

        elif [ "$INPUT" = "INTG" ]; then

                DBCONNECT_STRING=$DBCONNECT_STRING_CORP_POS_INTG

        else

                echo "Unkown parameter: $1"

                exit -1

        fi

fi

 

if [ $# -ne 2 ]

then

echo "Usage: `basename $0` {PORT-NUMBER} {MBEAN-NAME}"

exit -1

else 

RET=`expr match $1 "[0-9]*$"`

 

        if [ "$RET" -gt 0 ]; then

                       echo "Port number is: $1"

        else

echo "Invalid port number: $1"

exit -1

               fi

echo "MBean name is: $2"

fi

 

6. SVN revert or delete unversioned files in batch

svn st -u | awk -F "[ ]*" '{print $4}' | xargs svn revert

svn st -u | awk -F "[ \t]*" '{print $2}' | xargs rm -rf 

 

 

7. Remove version number in artifact id

echo ant-1.7.1.jar  | sed -e "s/-[0-9]\+\(\.[0-9]\)*\(_[A-Z][0-9]\)*\(-SNAPSHOT\)\?//g"

 

8. Find big files by du:

du -sh * 2>/dev/null | egrep "[0-9]+G"

du -s --block-size=M *  2>/dev/null| sort -rn

 

9. Check if specific class in jar file:

for i in `ls`; do jar tf $i | grep "ClassName" && echo $i; done

 

10. Collect footprint of CPU/MEM:

top -b  -d 1  -p pid  > stat.txt

 

11. Check the exact start time / running time of a specific process

ps -eo pid,lstart,etime | grep [pid]

 

12. Find PID of process which occupies specified port

/usr/sbin/lsof -i:[port] or netstat -ap | grep [port]

 

13. Find last reboot time of linux server

last reboot

 

 14. .bashrc

HOME=SOME_FOLDER

eval `dircolors ~/.dircolors`

PS1="\[\e[32;1m\][\$(date '+%m-%d %H:%M:%S')]\[\e[32;1m\][\[\e[36;1m\]\u\[\e[33;1m\]@\[\e[35;1m\]\h\[\e[33;1m\]:\[\e[36;1m\]\w\[\e[32;1m\]]$\[\e[0m\] "

 alias ll='ls -ltr --color=tty'

alias p='ps -eo pid,ppid,user,lstart,etime,args --no-headers --sort pid | grep -v $$ | awk '\''BEGIN {format = "\033[32m%5s \033[36m%5s \033[35m%-6s \033[33m%24s \033[36m%12s \033[0m%-s\n"; printf format, "PID", "PPID", "UID", "STARTED", "ELAPSED", "COMMAND"; printf format, "-----", "-----", "------", "------------------------", "------------", "--------------------" }; {printf "\033[32m%5s \033[36m%5s \033[35m%-6s \033[33m%-3s %-3s %-2s %-8s %-4s \033[36m%12s \033[0m", $1, $2, $3, $4, $5, $6, $7, $8, $9; for(i=10;i<NF;i++){printf $i " "}; print $NF}'\'''

function pg() {  

  p | egrep "PID|-----|$1" | grep -v egrep

} 

 

15. Create root user

#useradd -o -u 0 -g 0 -M -d /root -s /bin/bash admin

 

#passwd admin

 

16. Check cron jobs for each user in the system

cat /etc/passwd | cut -d: -f1  | xargs -t -i  crontab -l -u {}

 

17. Create SSH tunnel user

#userdel -r tunneluser

#useradd -M -s /usr/sbin/nologin tunneluser

#useradd -M -s /usr/bin/passwd tunneluser

 

18. Convert command line option to JVM arguments

if [ $# -gt 0 ]; then

    params=( "$@" )

    for param in "${params[@]}"; do

        if [ "`expr \"$param\" : \"--.*=.*\"`" -ne "0" ]; then

            param=${param/--/-D}

            JAVA_OPTIONS="$JAVA_OPTIONS $param"

        fi

    done

fi