Below are real-world examples practical Linux file management examples you can try on any test server.
Every command includes a quick explanation and a useful scenario. But, before trying the below Linux commands, I need to brew a great cup of specialty coffee at home.
Directory and File Basics
Create a folder for logs files:
mkdir logs
Create nested folders:
mkdir -p proj/some/folder/
Create an empty file with the touch command:
touch somefile.txt
Update file’s timestamp: (file that was already created)
touch somefile.txt
List all files with details:
ls -l
Show hidden files:
ls -la
Sort files by time:
ls -lt
Copy files:
cp file1.txt somedir/
Copy a directory recursively:
cp -r /dir/youdir backupdir/
Rename a file:
mv onefile.txt onefile-old.txt
Move to another folder:
mv mylog.log somelogsdir/
Remove a file:
rm filetoremove.txt
Remove a directory and contents:
rm -rf dirtoremove/
⚠️ Always double check before running the above command!
Remove empty folder:
rmdir emptydir/
If directory is NOT empty:
rm -rf notemptydir/
Find all .log files using the find command:
find /sampledir/dir-to-search -name "*.log"
The logic of the find command is:
find <location_to_search> -name "what-you-want-to-find"
Find files bigger than 100 MB:
find / -type f -size +100M
The logic of the above find command:
find <locationToSearch> -<typeOfFile> <file> -<sizeOfFile> +<largerThanMB>
Find and delete files older than 7 days:
find /somedir -type f -mtime +7 -delete
Find file by owner:
find /home -user paco
Detect file type using the file command:
file oneimage.png
Check binary:
file /usr/bin/ls
You should get an output like this:
/usr/bin/ls: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=ddcbef552f9c2ea0dbe2a1f38c312d26e0ac975b, stripped
Archiving & Compression
tar — bundle & compress:
Create a tar archive:
tar -cvf backit.tar proj/myfiles
The logic for the above is:
tar -<options> fileNameTobeCreated.tar <dir/filesYouWanttoCompress>
Extract a tar:
tar -xvf backit.tar
Create compressed tar.gz:
tar -czvf thisiscomp.tar.gz /etc/sshd
Extract tar.gz:
tar -xzvf tobeExtracted.tar.gz
cpio — copy files based on a list:
Archive files listed by find:
find /etc -type f | cpio -ov > thefiles.cpio
Extract a cpio file:
cpio -id < thefiles.cpio
dd command – block-level copying:
Clone a drive:
dd if=/dev/sda of=/dev/sdb bs=4M status=progress
Create a file of specific size:
dd if=/dev/zero of=thefile.img bs=1M count=100
Backup MBR (Master Boot Record):
dd if=/dev/sda of=mbr_backup.bin bs=512 count=1
Linux Compression Tools
Compress:
gzip afile.txt
Decompress the file:
gunzip afile.txt.gz
zip2 and bunzip2 examples. Higher compression, slower.
Compress:
bzip2 bigfile.iso
Decompress:
bunzip2 bigfile.iso.bz2
xz and unxz commands. Very high compression.
Compress:
xz somesql.sql
Decompress:
unxz somesqldb.sql.xz
Linux File Globbing (very useful!)
Globbing = smart wildcard matching. Very cool.
Match all .txt files:
ls *.txt
Match any file starting with “log”:
ls log*
Match files with one character:
ls thefile?.txt
This will match:
- file1.txt
- fileA.txt
- fileb.txt
- it will not match:
Match a range:
ls somefile[1-5].txt
Real-Life Sysadmin Examples Using Globbing
Delete all logs older than 7 days: (Cool way to keep your file system clean)
find /var/log -name "*.log" -mtime +7 -delete
Brief explanation of the above command:
/var/log → directory to search
-name "*.log" → match only *.log files
-mtime +7 → modified more than 7 days ago
–delete -> go ahead and delete the files
But, always remember this: Never delete blind! Check first:
find /var/log -type f -name "*.log" -mtime +7
