Linux commands cookbook

Linux commands cookbook

switch shell to another user

# the latter with "-" gets an environment as if another user just logged in
$ sudo su - ubuntu

change file's modify time

$ touch -m -d '1 Jan 2006 12:34' tmp
$ touch -m -d '1 Jan 2006 12:34' tmp/old_file.txt


delete old files under a directory

$ find /data/storage/tmp/* -mtime +2 | xargs rm -Rf
$ find /data/storage/tmp/* -mtime +2 -exec rm {} \;


append string to file in command line

# append
$ echo "the last line" >>

# replace
$ echo "replace all" >

rename sub-folders

$ for f in */migrations/; do mv -v "$f" "${f%???????????}south_migrations"; done


list history commands

$ export HISTTIMEFORMAT="%Y%m%d %T  "
$ history

find public IP

$ wget -qO- ; echo


count file lines

$ wc -l filename.txt

$ wc -l *.py

find files by name or content

$ find / -name

# 在現在的資料夾裡的全部檔案中搜尋字串,會自動搜尋子目錄
$ find . | xargs grep 'string'

$ find . -iname '*something*'

$ find *.html | xargs grep 'share_server.html'

# 搜尋當前目錄下的所有檔案
$ grep "sublime_jedi_goto" *.*

# 搜尋 doc/ 目錄下的所有 txt 檔案
$ grep "sublime_jedi_goto" doc/*.txt

list files by date

$ ls -lrt

extract info from a file

$ cat uwsgi.log | grep error

display contents of all files in the current directory

$ grep . *
$ grep . *.html

list used ports

# list open files for a process
$ lsof | grep uwsgi

$ lsof -i | grep LISTEN
$ lsof -i -n -P | grep LISTEN

$ sudo netstat -ntlp | grep uwsgi

$ sudo netstat -nulp

$ sudo netstat -nxlp

ping port

$ curl -I ""
$ curl -I ""

$ sudo apt-get install nmap
$ nmap -p 4505
$ nmap -p 8000
$ nmap -p 5672

$ telnet 4505


show network traffic and bandwidth

$ tcpdump -i eth0

$ sudo apt-get install tcptrack
$ tcptrack -i eth0


list running processes

# show all processes
$ pstree -a

# also show pid
$ pstree -ap

# 列出前 10 個最佔記憶體的 processes
$ ps aux | sort -nk +4 | tail

# 列出 mysql 相關的 processes
$ ps aux | grep 'worker process'
$ ps aux | grep uwsgi

# 樹狀顯示
$ ps auxf

# 搜尋 process 並以樹狀結果顯示 parent process
$ ps f -opid,cmd -C python

kill processes

# 列出目前所有的正在記憶體當中的程序
$ ps aux

# 匹配字串
$ ps aux | grep "mongo"

# 幹掉它
$ kill PID

# kill all processes matching a name
$ sudo killall -9 httpd
$ sudo killall salt
$ sudo pkill -f runserver
MySQL error codes

MySQL error codes

Show all MySQL error codes using the perror command.

$ for i in {1..190..1}; do perror "$i"; done
OS error code   1:  Operation not permitted
OS error code   2:  No such file or directory
OS error code   3:  No such process
OS error code   4:  Interrupted system call
OS error code   5:  Input/output error
OS error code   6:  No such device or address
OS error code   7:  Argument list too long
OS error code   8:  Exec format error
OS error code   9:  Bad file descriptor
OS error code  10:  No child processes
OS error code  11:  Resource temporarily unavailable
OS error code  12:  Cannot allocate memory
OS error code  13:  Permission denied
OS error code  14:  Bad address
OS error code  15:  Block device required
OS error code  16:  Device or resource busy
OS error code  17:  File exists
OS error code  18:  Invalid cross-device link
OS error code  19:  No such device
OS error code  20:  Not a directory
OS error code  21:  Is a directory
OS error code  22:  Invalid argument
OS error code  23:  Too many open files in system
OS error code  24:  Too many open files
OS error code  25:  Inappropriate ioctl for device
OS error code  26:  Text file busy
OS error code  27:  File too large
OS error code  28:  No space left on device
OS error code  30:  Read-only file system
OS error code  31:  Too many links
OS error code  32:  Broken pipe
OS error code  33:  Numerical argument out of domain
OS error code  34:  Numerical result out of range
OS error code  35:  Resource deadlock avoided
OS error code  36:  File name too long
OS error code  37:  No locks available
OS error code  38:  Function not implemented
OS error code  39:  Directory not empty
OS error code  40:  Too many levels of symbolic links
OS error code  42:  No message of desired type
OS error code  43:  Identifier removed
OS error code  44:  Channel number out of range
OS error code  45:  Level 2 not synchronized
OS error code  46:  Level 3 halted
OS error code  47:  Level 3 reset
OS error code  48:  Link number out of range
OS error code  49:  Protocol driver not attached
OS error code  50:  No CSI structure available
OS error code  51:  Level 2 halted
OS error code  52:  Invalid exchange
OS error code  53:  Invalid request descriptor
OS error code  54:  Exchange full
OS error code  55:  No anode
OS error code  56:  Invalid request code
OS error code  57:  Invalid slot
OS error code  59:  Bad font file format
OS error code  60:  Device not a stream
OS error code  61:  No data available
OS error code  62:  Timer expired
OS error code  63:  Out of streams resources
OS error code  64:  Machine is not on the network
OS error code  65:  Package not installed
OS error code  66:  Object is remote
OS error code  67:  Link has been severed
OS error code  68:  Advertise error
OS error code  69:  Srmount error
OS error code  70:  Communication error on send
OS error code  71:  Protocol error
OS error code  72:  Multihop attempted
OS error code  73:  RFS specific error
OS error code  74:  Bad message
OS error code  75:  Value too large for defined data type
OS error code  76:  Name not unique on network
OS error code  77:  File descriptor in bad state
OS error code  78:  Remote address changed
OS error code  79:  Can not access a needed shared library
OS error code  80:  Accessing a corrupted shared library
OS error code  81:  .lib section in a.out corrupted
OS error code  82:  Attempting to link in too many shared libraries
OS error code  83:  Cannot exec a shared library directly
OS error code  84:  Invalid or incomplete multibyte or wide character
OS error code  85:  Interrupted system call should be restarted
OS error code  86:  Streams pipe error
OS error code  87:  Too many users
OS error code  88:  Socket operation on non-socket
OS error code  89:  Destination address required
OS error code  90:  Message too long
OS error code  91:  Protocol wrong type for socket
OS error code  92:  Protocol not available
OS error code  93:  Protocol not supported
OS error code  94:  Socket type not supported
OS error code  95:  Operation not supported
OS error code  96:  Protocol family not supported
OS error code  97:  Address family not supported by protocol
OS error code  98:  Address already in use
OS error code  99:  Cannot assign requested address
OS error code 100:  Network is down
OS error code 101:  Network is unreachable
OS error code 102:  Network dropped connection on reset
OS error code 103:  Software caused connection abort
OS error code 104:  Connection reset by peer
OS error code 105:  No buffer space available
OS error code 106:  Transport endpoint is already connected
OS error code 107:  Transport endpoint is not connected
OS error code 108:  Cannot send after transport endpoint shutdown
OS error code 109:  Too many references: cannot splice
OS error code 110:  Connection timed out
OS error code 111:  Connection refused
OS error code 112:  Host is down
OS error code 113:  No route to host
OS error code 114:  Operation already in progress
OS error code 115:  Operation now in progress
OS error code 116:  Stale NFS file handle
OS error code 117:  Structure needs cleaning
OS error code 118:  Not a XENIX named type file
OS error code 119:  No XENIX semaphores available
OS error code 120:  Is a named type file
OS error code 121:  Remote I/O error
OS error code 122:  Disk quota exceeded
OS error code 123:  No medium found
OS error code 124:  Wrong medium type
OS error code 125:  Operation canceled
MySQL error code 126: Index file is crashed
MySQL error code 127: Record-file is crashed
MySQL error code 128: Out of memory
MySQL error code 130: Incorrect file format
MySQL error code 131: Command not supported by database
MySQL error code 132: Old database file
MySQL error code 133: No record read before update
MySQL error code 134: Record was already deleted (or record file crashed)
MySQL error code 135: No more room in record file
MySQL error code 136: No more room in index file
MySQL error code 137: No more records (read after end of file)
MySQL error code 138: Unsupported extension used for table
MySQL error code 139: Too big row
MySQL error code 140: Wrong create options
MySQL error code 141: Duplicate unique key or constraint on write or update
MySQL error code 142: Unknown character set used
MySQL error code 143: Conflicting table definitions in sub-tables of MERGE table
MySQL error code 144: Table is crashed and last repair failed
MySQL error code 145: Table was marked as crashed and should be repaired
MySQL error code 146: Lock timed out; Retry transaction
MySQL error code 147: Lock table is full;  Restart program with a larger locktable
MySQL error code 148: Updates are not allowed under a read only transactions
MySQL error code 149: Lock deadlock; Retry transaction
MySQL error code 150: Foreign key constraint is incorrectly formed
MySQL error code 151: Cannot add a child row
MySQL error code 152: Cannot delete a parent row
MySQL error code 153: No savepoint with that name
MySQL error code 154: Non unique key block size
MySQL error code 155: The table does not exist in engine
MySQL error code 156: The table already existed in storage engine
MySQL error code 157: Could not connect to storage engine
MySQL error code 158: Unexpected null pointer found when using spatial index
MySQL error code 159: The table changed in storage engine
MySQL error code 160: There's no partition in table for the given value
MySQL error code 161: Row-based binary logging of row failed
MySQL error code 162: Index needed in foreign key constraint
MySQL error code 163: Upholding foreign key constraints would lead to a duplicate key error in some other table
MySQL error code 164: Table needs to be upgraded before it can be used
MySQL error code 165: Table is read only
MySQL error code 166: Failed to get next auto increment value
MySQL error code 167: Failed to set row auto increment value
MySQL error code 168: Unknown (generic) error from engine
MySQL error code 169: Record was not update. Original values was same as new values
MySQL error code 170: It is not possible to log this statement
MySQL error code 171: The event was corrupt, leading to illegal data being read
MySQL error code 172: The table is of a new format not supported by this version
MySQL error code 173: The event could not be processed. No other handler error happened
MySQL error code 174: Got a fatal error during initialization of handler
MySQL error code 175: File too short; Expected more data in file
MySQL error code 176: Read page with wrong checksum
MySQL error code 177: Too many active concurrent transactions
MySQL error code 178: Record not matching the given partition set
MySQL error code 179: Index column length exceeds limit
MySQL error code 180: Index corrupted
MySQL error code 181: Undo record too big
MySQL error code 182: Invalid InnoDB FTS Doc ID
MySQL error code 183: Table is being used in foreign key check
MySQL error code 184: Tablespace already exists
MySQL error code 185: Too many columns
MySQL error code 186: Row in wrong partition
MySQL error code 187: Row is not visible by the current transaction
MySQL error code 188: Operation was interrupted by end user (probably kill command?)
MySQL error code 189: Disk full
MySQL error code 190: Incompatible key or row definition between the MariaDB .frm file and the information in the storage engine. You have to dump and restore the table to fix this
SSL23_GET_SERVER_HELLO: tlsv1 alert internal error (SNI) in Python 2.7.6

SSL23_GET_SERVER_HELLO: tlsv1 alert internal error (SNI) in Python 2.7.6

會發生在 Python 2.7.6 連 CloudFlare HTTPS 的時候
似乎是因為 2.7.6 不支援 Server-Name-Indication (SNI)
Python 2.7.9 之後才支援


SSL routines: SSL23_GET_SERVER_HELLO: tlsv1 alert internal error
SSLError: bad handshake: SysCallError(32, 'EPIPE')


$ sudo apt-get install libffi-dev libssl-dev
$ pip install -U urllib3[secure] ndg-httpsclient pyasn1