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How to study your flashcards.
Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key
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H key: Show hint (3rd side).h key
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130 Cards in this Set
- Front
- Back
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How to ignore cases in grep?
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grep -i foo
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Disk space for a folder
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du $folder | grep total
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Disk free space
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df -h \tmp
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Which shell are you using?
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echo $SHELL
or echo $shell |
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How do you grep a string?
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grep foo
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How do you see an output with less?
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env | less
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Check all environmental variables?
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env
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Make a variable available to other programs in your environment.
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export VARIABLE
or export VARIABLE=3 |
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Syntax difference between:
export and setenv |
export key=value
setenv key value |
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Shells use:
export and setenv |
sh and ksh: export
csh and tshell: setenv |
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View all files in a folder with ".txt" suffix.
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ls /dir/*txt
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List files per modification time.
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ls -lt
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Put a job in the background (automatically run last suspended job)
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ctrl -z
bg |
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Put a job in the foreground.
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fg
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Clean the terminal.
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ctrl + l
clear |
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Shutdown machine.
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shutdown
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Display current tasks executed by the Linux kernel.
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top
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Suspend a process.
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ctrl + z
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Kill a process.
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ctrl + c
or kill 12 |
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Where is a command located?
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tcsh: where fsl
bash: which fsl |
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Set a variable to a new value.
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VAR=3
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The last commands that I typed.
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history
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First element of a an array in Bash.
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Indexed by 0.
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Declare an array.
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declare -a ARRAY
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Assign a list of variables to an array.
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ARRAY=(v1 v2 ... vn)
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Combine declaration and assignment of an array.
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declare -a ARRAY=(v1 v2 ... vn)
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Read content of an array.
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echo ${ARRAY[*]}
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Assign value to any array's location.
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ARRAY[10000]=vinf
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Delete element of an array.
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unset ARRAY[1]
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Number of lines in a file.
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wc -l $FILE
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Number of words in a file.
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wc -w $FILE
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Use the result of a command for sthg else.
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echo $(head -n $i $FILE | tail -n 1)
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List directories only.
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ls -l | grep ^d
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Concatenate strings $file and .txt?
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echo ${file}.txt
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Padding with 0.
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printf %0${MAXLEN}d $NUM;
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RAM usage.
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free -m
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Exit a program.
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exit
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Return code for a success.
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0
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Return code(s) for a failure.
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All n>0.
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How to find a string in a set of files.
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grep -R string /folders/
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Emacs: Get info about current mode.
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M-x describe-mode
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Emacs: Get ALL keybindings.
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Help Menu: Describe: All Keys.
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Syntax for conditional.
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if [ $F == "$f ]; then ...; fi
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Space between if, while, or do and condition.
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while [ "$i" -le "$nFILES" ]; do
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Value in a conditional.
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if [ $var != "value" ]
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Space between variables and operator.
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if [ $V1 == $V2 ];
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Separator in an array of values.
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ARR=(V1 V2 V3)
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Formulate a mathematical expression.
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expr 4 '+' 6
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Signs to isolate a command.
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`command`
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Signs to enter a value.
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"value"
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Signs for BASH protected symbols.
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'+'
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Length of a string.
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echo ${#FILE}
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End of a string after the nth position.
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echo ${FILE:n}
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Redirect by appending.
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cmd >> output
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Redirect to new file.
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cmd > output
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Test a condition (COMMAND).
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test 10 -lt 5
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TRUE (exit status).
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0
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FALSE (exit status).
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1
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What is [
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It is a command, and should be followed by a space.
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Test a condition (BRACKETS).
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[ 10 -lt 5 ]
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Exit status of last command.
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echo $?
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Read the third column of a table.
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awk '{print $3}' ROI_MNI_V4.txt
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Total size of a file.
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stat -c%s foo
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What is the first line in a file?
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Line 1.
$i=1 |
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Exit code if no exit function?
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0 by default.
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Looping through a vector.
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for FILE in ${FILES[*]}; do
done |
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Check whether an expression is false.
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[ ! 5 -le 5 ]
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Is expr AND expr true?
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if [ expr ] && [ expr ];
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Is expr OR expr true?
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if [ expr || expr ];
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If file exists.
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if [ -f $FILE ]; then
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Update an index.
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let t=t+1
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Code for standard INPUT.
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0
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Code for standard OUTPUT.
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1
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Code for standard ERROR.
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2
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What is the standard output.
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The shell or screen.
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Open file in std output.
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cat file
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List files containing "string".
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ls -l *string*
or ls -l | grep string |
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Time a command.
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time cmd
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Submit a job and then leave a server.
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bg
exit |
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Requirements for remote login.
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Need a fix IP address.
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Unzipping any files.
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gunzip foo
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GNU zipping or compression.
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gzip foo
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Tarball and zip entire folder.
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tar cvz -f foo.tar.gz foo
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Contracted extension for .tar.gz
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.tgz
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Untar and unzip an archive.
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tar xvz -f foo.tar.gz
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Kill a job [command line].
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kill %1
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What is qsub for?
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Submit batch job to Grid Engine.
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How to use qsub?
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qsub -q rhe5b -b y -N foo bash ~/foo.sh
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Display groups (per cluster) queues.
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qstat -g c
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GUI interface for GRID Engine.
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qmon
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Queue stat for my jobs.
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qstat -u user
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Delete a job in the queue.
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qdel -f job-ID
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Process(es) Status.
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ps aux
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Does a directory exists?
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[ -d $folder ];
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Print columns 1 and 2.
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awk '{print $1,$2}' foo.txt
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Add a column of zero and boudiou.
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awk '{print 0,"bingo",$0}'
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What is $0 in awk?
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All the fields.
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Find and replace with awk.
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awk -v var=cool '{ gsub(/crap/,var,$0); print }' foo.txt
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Find and replace with awk (Two variables)
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awk -v V1=crap -v V2=cool '{ gsub(V1,V2,$0); print }' foo.txt
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Install a software.
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sudo apt-get install foo
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Re-install a software.
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sudo apt-get --reinstall install foo
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Upgrade all softwares.
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sudo apt-get upgrade
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Upgrade distribution.
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sudo apt-get dist-upgrade
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Which Linux version?
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uname -a
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List of printers.
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lpstat -a
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Alternative to SAMBA for printing.
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lpd:://
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Editing windows in Gnome.
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gconf-editor -> metacity
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aliases?
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alias
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Use ImageMagick for convertion.
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convert img.png img.ps
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Queues for all users on SGE.
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qstat -u "*"
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Deleted Files on BRC-MH.
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cd .snapshot
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Change both ownership and group.
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chown cgineste:cgineste foo
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Globbing?
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Use of wildcards.
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All .pdf files starting with a capital letter.
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[A-Z].pdf
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All .pdf files whose name is any character.
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?.pdf
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Change to the previous directory.
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cd -
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Recursively list current directory.
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ls -R
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List files in reverse time order.
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ls -rt
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Remove a directory.
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rmdir myDir
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Make subdirectory even if directory doesn't exist.
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mkdir -p myDir/subDir
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What other signs can replace the d in drwxrwx---
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- for a file
l for a link. |
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Recursively assign permissions in a directory.
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chmod -R myDir
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Print only the FIRST 100 lines of a file.
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head -100 myfile.txt
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Print the LAST 100 lines of a file.
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tail -100 myfile.txt
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Continuously update the last lines of a file.
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tail -f mylog.txt
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Display Linux tasks.
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top
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Show all the processes a user is running.
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ps -fu cgineste
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