CheatSheet: Linux Files
- PDF Link: cheatsheet-file-A4.pdf, Category: linux
- Blog URL: https://cheatsheet.dennyzhang.com/cheatsheet-file-A4
- Related posts: CheatSheet: Linux Process, CheatSheet: Linux Networking, #denny-cheatsheets
1.1 Check file
| Name | Comment |
|---|---|
| Show file content | cat /etc/hosts |
| Show file content with line numbers | cat -n /etc/hosts |
| Show with line numbers, excluding blank lines | cat -b /etc/hosts |
| Show the first 3 lines | head -n3 /etc/hosts |
| Show the first 20 bytes | head -c20 /etc/hosts |
| Show the last 3 lines | tail -n3 /etc/hosts |
| Show the last 20 bytes | tail -c20 /etc/hosts |
| Keep tailing log file | tail -f /var/log/system.log, taif /var/log/system.log |
| Show file starting from 4th line | more +4 /etc/hosts |
| Show the 4th line | sed -n '4p' /etc/hosts |
| Show 4th, 5th, 7th and 8th lines | sed -n '4,5p;7,8p' /etc/hosts |
| Show matched string with 3 lines before and after | grep -C 3 "127.0.0.1" /etc/hosts |
| For table-like file, show 2nd column | awk -F'\t' '{print $2}' /etc/hosts |
| For table-like file, swap 1st and 2nd columns | awk -F'\t' '{print $2,$1}' /etc/hosts |
| Find file encoding | file -i /var/log/corecaptured.log |
1.2 Find file
| Name | Summary |
|---|---|
| Basic find | find /home/mac/<myfolder> -name “my*.log” |
| Find files with two patterns | find . -iname “my*.log” -o -iname “my*.txt” |
| Find folder old than 3 days | find . -maxdepth 1 -type d -ctime +3 |
| Find files changed within 60 minutes | find /var/log -mmin 60 -type f |
| Find with ls details | find . \( -iname README.md \) -ls |
| Find files filtered by size | find /var/log -type f -size +50k -size -100k |
| Find files older than another file | find . -newer /tmp/file |
| Find files while excluding patterns | find . -name "*.log" -prune -o -name ".git" -prune -o -type f -print0 |
1.3 Find and delete
| Name | Summary |
|---|---|
| Find and delete with given names | find . -name Thumbs.db -delete |
| Recursively delete empty folders | find . -type d -empty -delete |
| Delete files haven’t been updated in 5 days | find . -mtime +5 -exec rm {} \; |
| Delete folders created older than 5 days | find . -name "npm-*" -type d -ctime +2 -exec rm -rf {} + |
1.4 Watch file
| Name | Comment |
|---|---|
| Show file changes | watch -d -n 1 stat /var/log/message |
| Keep tailing log files | tail -f /var/log/system.log, taif /var/log/system.log |
1.5 Copy file
| Name | Comment |
|---|---|
| Copy one file | cp /etc/hosts /tmp/hosts |
| Copy one folder | cp -r /usr/local/bin/ /tmp/bin/ |
| Copy for backup | cp /tmp/hosts{,.bak}, ls -lth /tmp/hosts* |
| Create a copy but ask confirmation for overwrite | cp -i ~/foo.txt /tmp/foo.txt |
| Create a copy for backup with timstamp as suffix | cp myfile.txt{,."$(date +%Y%m%d-%H%M%S)"} |
| Copy files by checking timestamp | rsync -av $src_dir $dest_dir |
| Copy files by comparing checksum | rsync -avc $src_dir $dest_dir |
1.6 Watch file
| Name | Command |
|---|---|
| Remove a file or folder | rm -rf <path> |
| Remove a file or an empty folder | rm -f <path> |
| Remove a file by inode | find <path> -inum 5555 -exec rm -i '{}' \; |
1.7 Diff File
| Name | Command |
|---|---|
| Diff two files | diff <file1> <file2> |
| Ignore uppercase and lowercase | diff -i <file1> <file2> |
| Diff output of two commands | diff <(date) <(somecommand) |
| Generate patch from two files | diff -Naur <file1> <file2> > diff.patch |
| Diff two directories | diff -r <dir1> <dir2> |
| Show only brief summary | diff -r --brief <dir1> <dir2> |
1.8 Make directory
| Name | Comment |
|---|---|
| Make directory. Report error, if existing | mkdir foo |
| Make directory. Avoid reporting error, if existing | mkdir -p foo |
| Make directory and its parents | mkdir -p foo/bar/dir1 |
| Make directories with the hierachy | mkdir -p foo/{bar,bad/{dir1,dir2}}, tree foo |
