ether This series is dedicated to exploring little-known—and occasionally useful—trinkets lurking in the dusty corners of UNIX-like operating systems. I frequently find myself reaching for the cut utility when writing scripts to extract one piece of data from a line, or to select specific fields from a log file. While I am familiar with its counterpart, paste, I don't employ it very often because I don't typically need its functionality. This perhaps has to do with the fact that I rarely work with text files containing lists. For shorter lists, I usually end up using a spreadsheet and for larger ones, a relational database. Both are valuable tools with their own strengths and weaknesses, but it is good to also know about standard utilities for working with lists. After uploading UNIX Curio #8 (HPR episode 4657), I felt like maybe I had been too dismissive of the comm utility in that episode and should talk more about tools that are useful when managing lists. I don't frequently find myself using paste 1, but can explain how it works. Briefly, it is a rough opposite of cut—when given multiple files as arguments, it assembles the first line from each one separated by tabs, then the second line, and so on. Instead of tabs, a different delimiter can be chosen with the -d option. Another option is -s, which swaps rows and columns so that the contents of each named file would appear on one line. While paste itself doesn't qualify as a UNIX Curio in my opinion, there is one feature that does: a hyphen can be given as an argument multiple times. In this special case, the output is taken line by line from standard input, but is spread across as many columns as there are hyphens. Example of using paste to turn the output of ls into columns. Because these columns are separated by tabs, they don't necessarily line up when a filename is eight or more characters long. The -1 is not required for the second ls command since that behavior is implied when output isn't going to a terminal. The -C option to ls usually gives nicer-looking output on a terminal—also, it lists in ascending order down by column. (Most implementations default to -C when output goes to a terminal.) If you want items ascending along rows like the paste example does, try ls -x instead. $ ls -1 /proc/net anycast6 arp bnep connector dev dev_mcast dev_snmp6 fib_trie fib_triestat hci icmp icmp6 if_inet6 igmp igmp6 ip6_flowlabel ip6_mr_cache ip6_mr_vif ip_mr_cache ip_mr_vif ip_tables_matches ip_tables_names [...35 more entries not shown...] $ ls /proc/net | paste - - - - anycast6 arp bnep connector dev dev_mcast dev_snmp6 fib_trie fib_triestat hci icmp icmp6 if_inet6 igmp igmp6 ip6_flowlabel ip6_mr_cache ip6_mr_vif ip_mr_cache ip_mr_vif ip_tables_matches ip_tables_names ip_tables_targets ipv6_route l2cap mcfilter mcfilter6 netfilter netlink netstat packet protocols psched ptype raw raw6 rfcomm route rt6_stats rt_acct rt_cache sco snmp snmp6 sockstat sockstat6