Some useful Unix commands

• The most basic: navigation: 
• cd, cd ..
• ls
• ls -alShr
• ls -alShr | less
• ls -alhF
• cp, mv, rm, rm -r 
• The locations in which the shell searches for executables:
• echo $PATH
• Other useful echo commands:
• echo $SHELL
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• Finding stuff:
• find command
• Find all files with name "*alpha*" :
• find . -name "*alpha*" -print
• List of all such files in a text file
• find . -name "*alpha*" -print >> list.txt
• Number of such files:
• find . -name "*alpha*" -print | wc -l
• Find all txt files created in the last 60 days: 
• find /home/you -iname "*.txt" -mtime -60 -print
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• awk command
• sed command
• grep command
• locate command
• List only directories...
• find . -type d -depth 1
• ls -F | grep /
• ls -ld -- */
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• Shell script: create many (in this example, 100) directories:
• for i in {1..100}; do mkdir subdirectory_$i; done
• mkdir subdirectory_{1..100}
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• Add pdf extension to all files in a folder:
• for i in *; do mv $i ${i}.pdf ; done
• Finding the location of the executable which the shell runs when a command is entered:
• which ls
• whereis gcc
• Current values of all environment variables:
• set
• printenv
• Counting 
• the number of lines in a file
• wc -l
• creative use
• ls -alshr > tmp.txt wc -l
• find . -name '*.f90' | xargs wc -l
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• redirect the output of a command into a file: 
• command > filename 
• Instead, if we wish to append in the file named filename:
• command >> filename 
• set > filename.txt;
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• Content of a text file:
• head, tail
• cat,
• vi, nano, pico
• less
• Use of | and >
• Login as a root user:
• sudo -i
• Getting help:
• man, man --help
• help
• whatis
• apropos
• info
• man 5 passwd
• man -a passwd
• Processes related information:
• top
• ps
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• System related info:
• System name 
• uname -s
• uname
• Network host name:
• unmae -n 
• Kernel version
• uname -v
• Info about kernel release:
• uname -r
• machine hardware name:
• uname -m
• machine processor architecture name
• uname -p
• All of the above info together
• uname -a
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• sysctl -n machdep.cpu.brand_string
• Hardware info:
• sysctl -a hw
• /usr/sbin/system_profiler SPHardwareDataType
• Storage related infor:
• /usr/sbin/system_profiler SPStorageDataTypesw_vers
• RAM:
• sysctl hw.memsize
• All CPU related info:
• sysctl -a | grep cpu
• Full info (this will take a lot of time and generate a lot of output, see help):
• /usr/sbin/system_profiler 
• /usr/sbin/system_profiler -h
• /usr/sbin/system_profiler -listDataTypes
• Disk space
• diskutil list
• df -h
• du -h
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