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Nima jahan bakhshian
Nima jahan bakhshian

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Linux common commands every developer should know

#linux #command #developer #programming

The command line is one of the most powerful and efficient ways to interact with Linux systems. For developers, knowing the commands can make tasks much faster and easier.
This article provides a reference of useful Linux commands for developers. this commands are organized by category so you can be easily found and used when needed.

Navigation and directory management

ls -> List directory contents

ls -l # long format (permissions, size, date)
ls -la # include hidden files
ls -lh # human-readable sizes
ls -lt # sort by modification time
ls -R # recursive listing
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cd -> Change directory

cd /absolute/path
cd .. # go up one level
cd - # switch to previous directory
cd ~ or just cd # go to home directory
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pwd -> Print working directory

pwd
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mkdir -> Create directories

mkdir <dir_name>
mkdir -p path/to/nested/dir # create parent directories if needed
mkdir -m 755 new_dir # set permissions while creating
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File operations

rm -> Remove files/directories

rm file.txt
rm -r directory/ # recursive delete
rm -rf directory/ # force recursive (dangerous!)
rm -i file # interactive confirmation
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cp -> Copy files/directories

cp file1 file2
cp -r source/ dest/ # recursive copy
cp -a source/ dest/ # archive mode (preserve attributes)
cp -v file dest/ # verbose output
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mv -> Move or rename

mv old_name new_name
mv file /path/to/destination/
mv -i file dest/ # interactive (ask before overwrite)
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Viewing searching content

cat -> Display or create files

cat file.txt
cat file1 file2 # concatenate multiple files
cat > newfile.txt # create/overwrite a file
cat >> file.txt # append to a file
cat -n file.txt # show line numbers
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grep -> Search text patterns

grep "pattern" file.txt
grep -r "pattern" . # recursive search
grep -i "pattern" file # case-insensitive
grep -n "pattern" file # show line numbers
grep -v "pattern" file # invert match (exclude)
grep -E "regex" file # extended regex
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find -> Locate files and directories

find . -name "*.js"
find /path -type f -name "*.log" # only files
find . -mtime -7 # modified in last 7 days
find . -size +10M # files larger than 10MB
find . -name "*.tmp" -delete # find and delete
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Permissions

chmod -> Change file permissions

chmod 755 script.sh # rwxr-xr-x
chmod +x script.sh # add execute permission
chmod -R 644 directory/ # recursive
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Process management

ps -> List running processes

ps aux # all processes with details
ps -ef # full format listing
ps aux | grep node # filter specific process
ps -u username # processes of a specific user
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kill / killall -> Terminate processes

kill PID # graceful termination (SIGTERM)
kill -9 PID # force kill (SIGKILL)
killall process_name # kill by name
kill -15 PID # same as default SIGTERM
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Archiving

tar -> Archive and compress

tar -czvf archive.tar.gz folder/ # create gzip archive
tar -xzvf archive.tar.gz # extract
tar -tzvf archive.tar.gz # list contents
tar -cjvf archive.tar.bz2 folder/ # bzip2 compression
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System resource monitoring

df -> Display disk space usage

df -h # human-readable sizes (GB/MB)
df -hT # show filesystem type
df -i # show inode usage
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du -> Estimate file/directory space usage

du -sh folder/ # total size of a folder (summary)
du -h --max-depth=1 # size of each subfolder
du -ah # show all files and directories
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free -> Display memory usage

free -h # human-readable
free -m # show in megabytes
free -s 5 # refresh every 5 seconds
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uptime -> Show system uptime and load average

uptime -p # pretty format (“up 2 days, 3 hours”)
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top -> Real-time overall system view

top # interactive view
Press M # sort by memory
Press P # sort by CPU
Press q # quit
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vmstat -> System memory, processes, CPU, I/O stats

vmstat 1 # update every 1 second
vmstat -s # summary of memory statistics
vmstat -d # disk statistics
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Process viewing

pstree -> Display processes in a tree structure

pstree # basic tree
pstree -p # show PIDs
pstree -u # show usernames
pstree -a # show command-line arguments
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Command history

history -> View previously executed commands

history # full list
history 20 # last 20 commands
!123 # re-run command number 123
!! # re-run the last command
history | grep "docker" # search past commands
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