• tr

    •  

     
     
     

    Sous emacs : remplacer un carriage return par un ¨;¨

    esc-x query-replace Ctrl q Ctrl J

    par ;

    Ctrl q donne acces aux caracteres de controle

    Ctrl j correspond au renturn.

    Sous emacs : remplacer 2 carriage return par un seul ;

    esc-x query-replace Ctrl q Ctrl j Ctrl q Ctrl j

    par Ctrl q Ctrl j
     
     

    The Unix program tr is used to translate between two sets of characters. Characters specified in one set are converted to the matching character in the second set. Thus, to convert the Ctrl-m of a Mac OS text file to the line feed (Ctrl-j) of a Unix text file, at the Unix command line, enter: 

      tr '\r' '\n' < macfile.txt > unixfile.txt
    Here, \r and \n are special escape sequences that tr interprets as Ctrl-m (a carriage return) and Ctrl-j (a line feed), respectively. Thus, to convert a Unix text file to a Mac OS text file, enter: 
      tr '\n' '\r' < unixfile.txt > macfile.txt
    Note: The escape sequences must be surrounded by quotes for these commands to work.
     
     
  • awk

    •  

     
      To replace all letters, numbers, parenthesis and "_" and "^" by "-" in the file head enter :
      nawk '{ gsub(/[a-zA-Z0-9"^""_""("")"]/, "+");print $0;}' head.csv
     
     

    To use awk to convert a Mac OS file to Unix, at the Unix prompt, enter: 

      awk '{ gsub("\r", "\n"); print $0;}' macfile.txt > unixfile.txt
    To convert a Unix file to Mac OS using awk, at the command line, enter: 
      awk '{ gsub("\n", "\r"); print $0;}' unixfile.txt > macfile.txt
    On some systems, the version of awk may be old and not include the function gsub. If so, try the same command, but replace awk with gawk or nawk.
     
     

    To replace the remove all lines starting with #, enter : 

    awk '{if ( substr($0,1,1)!="#") print $0}' list_2mass.tsv


    To replace the remove all lines starting with either # or carriage return or SPACE, enter : 

    awk '{if (substr($0,1,1)!="#"&&substr($0,1,1)!='\n'&&substr($0,1,1)!=" ") print $0}' list_2mass.tsv
     
  • egrep

    • It can also be done with egrep 
    egrep -v '(^\#|^ $|^$|^  $)' < list2.tsv
  • sed

    • 14 of the most common sed commands for one-line use.
    1.     Replace a newline to \\followed by a newline
      sed 's/$/\\\\/' final.tex
     
    1.     Double space a file
       sed G file
     
    1.    Triple space a file
       sed 'G;G' file
     
    1.    Under UNIX: convert DOS newlines (CR/LF) to Unix format
       sed 's/.$//' file    # assumes that all lines end with CR/LF
       sed 's/^M$// file    # in bash/tcsh, press Ctrl-V then Ctrl-M
     
    1.    Under DOS: convert Unix newlines (LF) to DOS format
       sed 's/$//' file                     # method 1
       sed -n p file                        # method 2
     
    1.    Delete leading whitespace (spaces/tabs) from front of each line
       # (this aligns all text flush left). '^t' represents a true tab
       # character. Under bash or tcsh, press Ctrl-V then Ctrl-I.
       sed 's/^[ ^t]*//' file
     
    1.   Delete trailing whitespace (spaces/tabs) from end of each line
       sed 's/[ ^t]*$//' file               # see note on '^t', above
     
    1.    Delete BOTH leading and trailing whitespace from each line
       sed 's/^[ ^t]*//;s/[ ^]*$//' file    # see note on '^t', above
     
    1.    Substitute "foo" with "bar" on each line
       sed 's/foo/bar/' file        # replaces only 1st instance in a line
       sed 's/foo/bar/4' file       # replaces only 4th instance in a line
       sed 's/foo/bar/g' file       # replaces ALL instances within a line
     
    1.    Substitute "foo" with "bar" ONLY for lines which contain "baz"
       sed '/baz/s/foo/bar/g' file
     
    1.    Delete all CONSECUTIVE blank lines from file except the first.
       # This method also deletes all blank lines from top and end of file.
       # (emulates "cat -s")
      sed '/./,/^$/!d' file       # this allows 0 blanks at top, 1 at EOF
       sed '/^$/N;/\n$/D' file     # this allows 1 blank at top, 0 at EOF
     
    1.    Delete all leading blank lines at top of file (only).
       sed '/./,$!d' file
     
    1.    Delete all trailing blank lines at end of file (only).
       sed -e :a -e '/^\n*$/N;/\n$/ba' file
     
    1.    If a line ends with a backslash, join the next line to it.
       sed -e :a -e '/\\$/N; s/\\\n//; ta' file
     
    1.    If a line begins with an equal sign, append it to the
       # previous line (and replace the "=" with a single space).
       sed -e :a -e '$!N;s/\n=/ /;ta' -e 'P;D' file
     
  • Perl

    •  

     
     
     
     
     

    To convert a Mac OS text file to a Unix text file using Perl, at the Unix shell prompt, enter: 

      perl -p -e 's/\r/\n/g'  < macfile.txt > unixfile.txt
    To convert from a Unix text file to a Mac OS text file with Perl, at the Unix shell prompt, enter: 
      perl -p -e 's/\n/\r/g' < unixfile.txt > macfile.txt